Tuesday, January 18, 2011
Monday, January 17, 2011
Math Tricks
Math can be terrifying for many people. This list will hopefully improve your general knowledge of mathematical tricks and your speed when you need to do math in your head.
1. The 11 Times Trick
We all know the trick when multiplying by ten – add 0 to the end of the number, but did you know there is an equally easy trick for multiplying a two digit number by 11? This is it:
Take the original number and imagine a space between the two digits (in this example we will use 52:
5_2
Now add the two numbers together and put them in the middle:
5_(5+2)_2
That is it – you have the answer: 572.
If the numbers in the middle add up to a 2 digit number, just insert the second number and add 1 to the first:
9_(9+9)_9
(9+1)_8_9
10_8_9
1089 – It works every time.
2. Quick Square
If you need to square a 2 digit number ending in 5, you can do so very easily with this trick. Mulitply the first digit by itself + 1, and put 25 on the end. That is all!
252 = (2x(2+1)) & 25
2 x 3 = 6
625
3. Multiply by 5
Most people memorize the 5 times tables very easily, but when you get in to larger numbers it gets more complex – or does it? This trick is super easy.
Take any number, then divide it by 2 (in other words, halve the number). If the result is whole, add a 0 at the end. If it is not, ignore the remainder and add a 5 at the end. It works everytime:
2682 x 5 = (2682 / 2) & 5 or 0
2682 / 2 = 1341 (whole number so add 0)
13410
Let’s try another:
5887 x 5
2943.5 (fractional number (ignore remainder, add 5)
29435
4. Multiply by 9
This one is simple – to multiple any number between 1 and 9 by 9 hold both hands in front of your face – drop the finger that corresponds to the number you are multiplying (for example 9×3 – drop your third finger) – count the fingers before the dropped finger (in the case of 9×3 it is 2) then count the numbers after (in this case 7) – the answer is 27.
5. Multiply by 4
This is a very simple trick which may appear obvious to some, but to others it is not. The trick is to simply multiply by two, then multiply by two again:
58 x 4 = (58 x 2) + (58 x 2) = (116) + (116) = 232
6. Calculate a Tip
If you need to leave a 15% tip, here is the easy way to do it. Work out 10% (divide the number by 10) – then add that number to half its value and you have your answer:
15% of $25 = (10% of 25) + ((10% of 25) / 2)
$2.50 + $1.25 = $3.75
7. Tough Multiplication
If you have a large number to multiply and one of the numbers is even, you can easily subdivide to get to the answer:
32 x 125, is the same as:
16 x 250 is the same as:
8 x 500 is the same as:
4 x 1000 = 4,000
16 x 250 is the same as:
8 x 500 is the same as:
4 x 1000 = 4,000
8. Dividing by 5
Dividing a large number by five is actually very simple. All you do is multiply by 2 and move the decimal point:
195 / 5
Step1: 195 * 2 = 390
Step2: Move the decimal: 39.0 or just 39
Step2: Move the decimal: 39.0 or just 39
2978 / 5
step 1: 2978 * 2 = 5956
Step2: 595.6
Step2: 595.6
9. Subtracting from 1,000
To subtract a large number from 1,000 you can use this basic rule: subtract all but the last number from 9, then subtract the last number from 10:
1000
-648
-648
step1: subtract 6 from 9 = 3
step2: subtract 4 from 9 = 5
step3: subtract 8 from 10 = 2
step2: subtract 4 from 9 = 5
step3: subtract 8 from 10 = 2
answer: 352
10. Assorted Multiplication Rules
Multiply by 5: Multiply by 10 and divide by 2.
Multiply by 6: Sometimes multiplying by 3 and then 2 is easy.
Multiply by 9: Multiply by 10 and subtract the original number.
Multiply by 12: Multiply by 10 and add twice the original number.
Multiply by 13: Multiply by 3 and add 10 times original number.
Multiply by 14: Multiply by 7 and then multiply by 2
Multiply by 15: Multiply by 10 and add 5 times the original number, as above.
Multiply by 16: You can double four times, if you want to. Or you can multiply by 8 and then by 2.
Multiply by 17: Multiply by 7 and add 10 times original number.
Multiply by 18: Multiply by 20 and subtract twice the original number (which is obvious from the first step).
Multiply by 19: Multiply by 20 and subtract the original number.
Multiply by 24: Multiply by 8 and then multiply by 3.
Multiply by 27: Multiply by 30 and subtract 3 times the original number (which is obvious from the first step).
Multiply by 45: Multiply by 50 and subtract 5 times the original number (which is obvious from the first step).
Multiply by 90: Multiply by 9 (as above) and put a zero on the right.
Multiply by 98: Multiply by 100 and subtract twice the original number.
Multiply by 99: Multiply by 100 and subtract the original number.
Multiply by 6: Sometimes multiplying by 3 and then 2 is easy.
Multiply by 9: Multiply by 10 and subtract the original number.
Multiply by 12: Multiply by 10 and add twice the original number.
Multiply by 13: Multiply by 3 and add 10 times original number.
Multiply by 14: Multiply by 7 and then multiply by 2
Multiply by 15: Multiply by 10 and add 5 times the original number, as above.
Multiply by 16: You can double four times, if you want to. Or you can multiply by 8 and then by 2.
Multiply by 17: Multiply by 7 and add 10 times original number.
Multiply by 18: Multiply by 20 and subtract twice the original number (which is obvious from the first step).
Multiply by 19: Multiply by 20 and subtract the original number.
Multiply by 24: Multiply by 8 and then multiply by 3.
Multiply by 27: Multiply by 30 and subtract 3 times the original number (which is obvious from the first step).
Multiply by 45: Multiply by 50 and subtract 5 times the original number (which is obvious from the first step).
Multiply by 90: Multiply by 9 (as above) and put a zero on the right.
Multiply by 98: Multiply by 100 and subtract twice the original number.
Multiply by 99: Multiply by 100 and subtract the original number.
Bonus: Percentages
Yanni in comment 23 gave an excellent tip for working out percentages, so I have taken the liberty of duplicating it here:
Find 7 % of 300. Sound Difficult?
Percents: First of all you need to understand the word “Percent.” The first part is PER , as in 10 tricks per listverse page. PER = FOR EACH. The second part of the word is CENT, as in 100. Like Century = 100 years. 100 CENTS in 1 dollar… etc. Ok… so PERCENT = For Each 100.
So, it follows that 7 PERCENT of 100, is 7. (7 for each hundred, of only 1 hundred).
8 % of 100 = 8. 35.73% of 100 = 35.73
But how is that useful??
8 % of 100 = 8. 35.73% of 100 = 35.73
But how is that useful??
Back to the 7% of 300 question. 7% of the first hundred is 7. 7% of 2nd hundred is also 7, and yep, 7% of the 3rd hundred is also 7. So 7+7+7 = 21.
If 8 % of 100 is 8, it follows that 8% of 50 is half of 8 , or 4.
Break down every number that’s asked into questions of 100, if the number is less then 100, then move the decimal point accordingly.
EXAMPLES:
8%200 = ? 8 + 8 = 16.
8%250 = ? 8 + 8 + 4 = 20.
8%25 = 2.0 (Moving the decimal back).
15%300 = 15+15+15 =45.
15%350 = 15+15+15+7.5 = 52.5
8%200 = ? 8 + 8 = 16.
8%250 = ? 8 + 8 + 4 = 20.
8%25 = 2.0 (Moving the decimal back).
15%300 = 15+15+15 =45.
15%350 = 15+15+15+7.5 = 52.5
Also it’s usefull to know that you can always flip percents, like 3% of 100 is the same as 100% of 3.
35% of 8 is the same as 8% of 35.
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Uses for Static Electricity
by Kokul
Although static electricity can be a nuisance—like getting shock when you touch a doorknob or having static cling on your clothes—it has a number of beneficial uses. The forces of attraction between charged particles caused by static electricity are used in air pollution control, xerography and automobile painting.
Questions you may have include:
- How is static electricity used in air pollution control?
- How does a Xerox machine work?
- How is static electricity used to paint cars?
This lesson will answer those questions. There is a mini-quiz near the end of the lesson.
Useful tools: Metric-English Conversion | Scientific Calculator.
Pollution control
Static electricity is used in pollution control by applying a static charge to dirt particles in the air and then collecting those charged particles on a plate or collector of the opposite electrical charge. Such devices are often called electrostatic precipitators.
Smokestacks
Factories use static electricity to reduce pollution coming from their smokestacks. They give the smoke an electric charge. When it passes by electrodes of the opposite charge, most of the smoke particles cling to the electrodes. This keeps the pollution from going out into the atmosphere.
How a smokestack electrostatic precipitator works
Air fresheners
Some people purchase what are called air ionizers to freshen and purify the air in their homes. They work on a similar principle as the smokestack pollution control. These devices strip electrons from smoke molecules, dust particles, and pollen in the air, just as what happens in creating static electricity.
These charged dust and smoke particles are then attracted to and stick to a plate on the device with the opposite charge. After a while, much of the pollution is drawn from the air.
Since charged particles will also stick to neutral surfaces, some of them can stick to the wall near the ionizer, making it very dirty and difficult to clean.
Xerography
Your photocopier or Xerox machine uses static electricity to copy print to a page. This is done through the science of xerography.
One version of this device electrically charges ink so that it will stick to the paper in the designated areas. Another version of a photocopier uses charges to stick the ink to a drum, which then transfers it to the paper.
Painting cars
Some automobile manufacturers use static electricity to help them paint the cars they make. The way this works is that they first prepare the car's surface and then put it in a paint booth. Next, they give the paint an electrical charge and then spray a fine mist of paint into the booth. The charged paint particles are attracted to the car and stick to the body, just like a charged balloon sticks to a wall. Once the paint dries, it sticks much better to the car and is smoother because it is evenly distributed.
Summary
Uses of static electricity include pollution control, Xerox machines, and painting. They use the property that opposite electrical charges attract. There are other uses involving the properties of repulsion and the creating of static electricity sparks.
Use your knowledge of static electricity to benefit mankind
Resources
The following resources provide information on this subject:
Websites
Xerography and Photocopying - references from the University of Delaware
Xerography: Chester Carlson's Impossible Dream - history of the invention of xerography
Electrostatic Precipitators for Power Plants - from Arizona State University School of Engineering
Books
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Mini-quiz to check your understanding
What is a mirage?
Under a baking sun, a weary traveller trudges across a seemingly never-ending expanse of desert. Looking up, he suddenly spots something in the distance: a sparkling lake. He rubs his eyes. It’s still there. Picking up the pace in glee he strides ahead… only for the water to melt into thin air.
You might think our traveller was hallucinating, but mirages are a naturally-occurring optical illusion. In cartoons, a mirage is often depicted as a peaceful, lush oasis lying in the shade of swaying palm trees, but in reality it is much more likely to look like a pool of water.
The illusion results from the way in which light is refracted (bent) through air at different temperatures. Cold air is denser than warm air, and therefore has a greater refractive index. This means that as light passes down from cool to hot air, it gets bent upwards towards the denser air and away from the ground (see diagram).
To your eyes, these distorted rays seem to be coming from the ground, so you perceive a refracted image of the sky on the ground. This looks just like a reflection on the surface of a pool of water, which can easily cause confusion.
1. There’s no need to trek to the desert to see a mirage: they are very common on roads. In fact, likely locations include anywhere where the ground can absorb a lot of heat. If you’ve ever walked barefoot on hot tarmac or sand, then you’ll know just how hot they can get! A hot ground warms up the air immediately above it, creating a sharp temperature gradient in the air – the first ingredient of a good mirage.
2. Make sure you can see ahead of you well into the distance. The most spectacular mirages occur in wide expanses of flat land as too many hills, dips or bumps will prevent the refracted light from reaching your eyes.
3. Check the weather forecast. If you see a huge puddle ahead on a rainy day you’d be better off steering well clear, as mirages are far more likely to found during dry, sunny weather.
You might think our traveller was hallucinating, but mirages are a naturally-occurring optical illusion. In cartoons, a mirage is often depicted as a peaceful, lush oasis lying in the shade of swaying palm trees, but in reality it is much more likely to look like a pool of water.
The illusion results from the way in which light is refracted (bent) through air at different temperatures. Cold air is denser than warm air, and therefore has a greater refractive index. This means that as light passes down from cool to hot air, it gets bent upwards towards the denser air and away from the ground (see diagram).
To your eyes, these distorted rays seem to be coming from the ground, so you perceive a refracted image of the sky on the ground. This looks just like a reflection on the surface of a pool of water, which can easily cause confusion.
A beginner’s guide to mirage spotting
1. There’s no need to trek to the desert to see a mirage: they are very common on roads. In fact, likely locations include anywhere where the ground can absorb a lot of heat. If you’ve ever walked barefoot on hot tarmac or sand, then you’ll know just how hot they can get! A hot ground warms up the air immediately above it, creating a sharp temperature gradient in the air – the first ingredient of a good mirage.
2. Make sure you can see ahead of you well into the distance. The most spectacular mirages occur in wide expanses of flat land as too many hills, dips or bumps will prevent the refracted light from reaching your eyes.
3. Check the weather forecast. If you see a huge puddle ahead on a rainy day you’d be better off steering well clear, as mirages are far more likely to found during dry, sunny weather.
Short Notes
Science 10 Provincial Notes
UNIT 1 Sustaining Earth’s Ecosystem
Chapter 1: Biomes and Ecosystems
• Section 1.1- Biomes
• Section 1.2- Ecosystems
Chapter 2: Energy Flow and Nutrient Cycles
• Section 2.1- Energy Flow in Ecosystems
• Section 2.2- Nutrient Cycles in Ecosystems
• Section 2.3- Effects of Bioaccumulation on Ecosystems.
Chapter 3: Ecosystems Changing
• Section 3.1- How changes Occur Naturally
• Section 3.2- How Humans Influence Ecosystems
• Section 3.3- Introduced Species
UNIT 2 Chemical Reactions and Radioactivity
Chapter 4: Atomic Theory explains the formation of compounds
• Section 4.1- Atomic Theory and Bonding
• Section 4.2- Names and Formulas
• Section 4.3- Chemical Equations
Chapter 5: Compounds are classified in different ways
• Section 5.1- Acids and Bases
• Section 5.2- Salts
• Section 5.3- Organic Compounds
Chapter 6: Chemicals Reactions
• Chapter 6.1- Types of Chemical Reactions
• Section 6.2- Factors Affecting Chemical Reactions
Chapter 7: The Atomic Theory
• Section 7.1- Atomic Theory, Isotopes and Radioactive Decay
• Section 7.2- Half-Life
• Section 7.3- Nuclear Reactions
UNIT 3 Motion
Chapter 8: Average Velocity
• Section 8.1- The Language of Motion
• Section 8.2- Average Velocity
Chapter 9: Acceleration
• Section 9.1- Describing Acceleration
• Section 9.2- Calculating Acceleration
UNIT 4 Energy Transfer in Natural Systems
Chapter 10: The Kinetic Molecular Theory
• Section 10.1- Temperature, Thermal Energy and Heat
• Section 10.2- Energy Transfer in the Atmosphere
Chapter 11: Climate Change
• Section 11.1- Natural Causes of Climate Change
• Section 11.2- Human Activity and Climate Change
Chapter 12: Thermal Energy transfer Drives Plate Tectonics
• Section 12.1- Evidence for Continental Drift
• Section 12.2- Features of Plate Tectonics
Chapter 1: Biomes and Ecosystems
Section 1.1- Biomes
Abiotic and Biotic
• Biotic- living components:
- Organisms
- Plants, animals, fungi and bacteria
- Interact with each other and with the physical and chemical environment in which they live in
• Abiotic- non- living components:
- Sunlight, soli, moisture and temperature
Biome
• Includes large regions that have similar biotic components:
- Similar temperature and amount of rainfall
- There are 8 terrestrial (land based) biomes
1. Boreal Forest
2. Desert
3. Grassland
4. Permanent Ice
5. Temperate Deciduous Forest
6. Temperate Rainforest
7. Tropical Rainforest
8. Tundra
Factors That Influence Biomes
• Temperature and Precipitation:
- Precipitation- rain, snow, mist and fog
- Most important abiotic factors that influence the characteristics of biomes
- Animals and plants can only survive in specific temperatures and the amount of precipitation
- Graph- y axis: annual precipitation and x axis: find the intersection with the average annual temperature
• Latitude:
- Abiotic factor that affects the temperature and precipitation
- Distance measured in degrees north or south from the equator
- Tropical zone: is close to equator, it receives more direct sunlight and has warm temps.
- Sun rays less intense farther away from the equator, the temp. In these zones are lower that they are at the equator.
- At the equator- the direct sunlight heats moist air, which rises, cools in the upper atmosphere and falls on earth as rain
- Land or oceans on the equator receive greatest amount of precipitation
• Elevation:
- The height of a land mass above sea level
- Affects temperature because atmosphere is thinner at a higher elevation which means it retains less heart
- Windward side of a mountain: clouds filled with moisture rise and cool then release rain or snow
- Leeward side- (sheltered by the wind) the air warms again, which allows it to absorb water creating a dry land area
• Ocean Currents:
- Also and abiotic factor that affects temp and precipitation
- Makes biome warmer and wetter
Climatographs
• Climate and Climotographs:
- Climate: average pattern of weather conditions that occur in a region
- Climatograph: a graph of climate data usually obtained over 30 years from local weather observations
- Month of the years is shown is shown on the horizontal axis
- The average temp is shown on the right vertical axis
- The average propitiations is shown on the left vertical axis
Adaptations and Biomes
• Adaption’s:
- Characteristics that enable organisms to better survive and reproduce. There are 3 types:
a) Structural adaptation- physical feature of an organisms having a specific function that contributes to the survival of the organism
Example: pine trees are cone-shaped and therefore get rid of snow.
Example: Arctic fox has thick, white coat in the winter and a brownish-grey one in the simmer for camouflage.
b) Physiological Adaptation- physical or chemical event that occurs within the body of the organism that enables survival.
Example: wolves can contain a constant body temperature no matter the weather conditions.
c) Behavioral Adaptations- what an organism does to survive in the unique conditions of its environment. (Feeds, mates, cares for young, migrate, hibernate or escape from predators.)
Example: the owl lines his nest with grass, which keeps it cool during the day and warm at night.
The Biomes:
1. Tundra • Located in the upper northern hemisphere
• Very cold and dry
• Permanently frozen soil (permafrost)
• Plants are short and there are few trees
• Animals have compact bodies and shorter legs and ears which reduce heat loss
2. Boreal Forest • Found in the far north
• Below freezing half the year
• Mainly coniferous (cone-bearing) trees
3. Temperate Deciduous Forest • Located in temperate regions- mostly eastern North American, eastern Asia and Europe
• Trees lose their leaves in winter (tall tress)
• Large seasonal changes with four distinct seasons
4. Temperate Rainforest • Found along coastlines where oceans winds drops large amounts of moisture
• Coast of Chile, BC, New Zealand, part of Australia
• Cool and very wet (fog which provides moisture and rainfall)
• Allows trees (mainly evergreens) to grow very tall
5. Grassland • Occurs in temperate and tropical regions
• Canada, North America, Russia, Africa, South America, northern Australia
• Covered with grasses that have deep roots, which are well adapted to droughts
• Limited rainfall and land is mainly flat
• Large grazing animals
6. Tropical Rainforest • Found in wide band around the equator
• Northern South America, Central America, central Africa and southeast Asia
• Wet and warm all year around
• Allows the growth of a dense canopy of tall tress
• Hass the greatest diversity of animals but few large a mammals
7. Desert • Occur in temperate and tropical regions
• Days are hot and nights are cold
• Rainfall is minimal and plans and animals are adapter to reduce water loss
• Reptiles are common and have thick skin and scales
8. Permanent Ice • Includes the polar land masses and large polar ice caps
• Arctic, Greenland and Antarctica
• The few animals that live there are well insulated against the extreme cold
Section 1.2- Ecosystems
Parts of an Ecosystem
• Ecosystem
- Has abiotic factors- oxygen, water, nutrients, light and soil
- Biotic factors- plants and animals, microorganisms.
- Within an ecosystem is a habitat which is a place in which an organism lives
Abiotic Interactions in Ecosystems
• Interactions:
- Organisms have special roles-or niches in their ecosystem
- The way it contributes to and fits into its environment
- Biotic interactions are structured form smallest to largest in and ecological hierarchy
a) A species: is a group of closely related organisms that can reproduce with one another
b) Population- all the members of a species within an ecosystem
c) Community- populations of a different species that interact in a specific ecosystem
Biotic Interactions in Ecosystems
• Symbiosis:
- The interaction of two different organisms that live in close association
- Communalism, mutualism, parasitism, competition, predation, and mimicry
Interaction Result Example
Commensalism One Organism benefits and the other is neither helped nor harmed. Barnacles attach to whales and are transported to new locations in the ocean.
Mutualism Both organisms benefit and sometimes neither species can survive without the other. In lichen, the alga produces sugars and oxygen for the fungus, which provides carbon dioxide and water for the alga.
Parasitism One species benefits and another is harmed. Hookworms attach to the gut wall and obtain nourishments from their host’s blood.
Competition Organisms require the same resource (i.e. food) in the same place at the same time. Spotted knapweed release chemicals into the soil, which prevents the growth of other plants.
Predation One organism (the predator) eats all or part of another organism (the prey). Cougars have sharp, pointed teeth to catch prey.
Mimicry A prey animal mimics another species that is dangerous or tastes bad to avoid being eaten. Viceroy butterflies look like bitter-tasting monarch butterflies and are avoided by predators.
Chapter 2: Energy Flow and Nutrient Cycles
Section 2.1- Energy Flow in Ecosystems
• Energy Flow:
- Producers: plants that produce food in the form of carbohydrates during photosynthesis
- Consumer: a insects that eats the plant
• Dead organisms:
- Decomposition: the breakdown of organic wastes and dead organism
- Biodegradation: when living organisms carry out decomposition
a) Detrivores, such as small insects, earthworms, bacteria and fungi, obtain energy and nutrients by eating dead plants and animals, as well as animal waste
b) Decomposers, such as bacteria and fungi, change wastes and dead organisms into nutrients that can be used by plants and animals
Food Chains and Webs
• Food Chains
- Show the flow of energy from plant to animal and from animal to animal
- Each step in a food chain is called a trophic level
- Detrivores: consumers that obtain energy at every trophic level and nutrients by eating small dead stuff
- Herbivores: primary consumers that eat plants
- Carnivores: secondary consumers that eat primary consumer
Trophic
Level Organism Energy Source Example
1st Primary producer Obtain energy from the sun Grass, algae
2nd Primary consumer Obtain energy from primary producers Grasshoppers, krill
3rd Secondary consumer Obtain energy from primary consumer Frogs, crabs
4th Tertiary consumer Obtain energy from secondary consumers Hawks, sea otters
• Food webs:
- Interconnected food chains
- Animals are in several food chains because they eat or get eaten by several organisms
• Food Pyramid:
- Shows the loss of energy from one trophic level to another
- Not all energy in incorporated into the consumers tissues
- Between 80 and 90% of energy is used for chemical reactions and is lost as heat
- Ecosystems can support fewer organisms at higher trophic levels, as less energy reaches these levels
Section 2.2- Nutrient Cycles in Ecosystems
The Carbon Cycle
• Cycled through living and decaying organisms, the atmosphere, bodies of water and soil and rock
• Photosynthesis:
- It is a chemical reaction that converts solar energy into chemical energy by an important process in which carbon and oxygen cycle through the ecosystem
- Energy (sunlight) + 6CO2 + 6H2 * C6H1206 + 602
• Cellular Respiration:
- Plants and animals breath out carbon dioxide back into the atmosphere by converting carbohydrates and oxygen into carbon dioxide and water
- C6H1206 (carbohydrates) + 602 * 6CO2 +6HO2 + 6H2O + energy
• Decomposition:
- Breaks down dead organic matter
- Examples of decomposers are bacteria and fungi that convert organic molecules back into carbon dioxide, which then is released into the atmosphere
• Ocean Process and Human Activity:
- Ocean process dissolves carbon dioxide that is stored in oceans
- Human activities are burning foil and clearing land which both release carbon quickly
The Nitrogen Cycle
• Component of DNA and proteins, which are essential for the life, processes that take place inside the cell.
• Most nitrogen is stored in the atmosphere (N2 nitrogen gas)
• Nitrogen Fixation:
- The process in which nitrogen gas is converted into compounds that conation nitrate or ammonium which are useful for plants
- Nitrogen fixation occurs in: atmosphere, soil and in water bodies
• Nitrification an Uptake:
- In Nitrification ammonium (NH4+) is converted into nitrate (NO3-)
- Takes place in two stages
- First stage: certain species of nitrifying bacteria convert ammonium into nitrate.
- Second stage: different species of nitrifying bacteria convert nitrite into nitrate
- The uptake is where useable forms of nitrogen are taken up by plant roots and included into plant proteins
• Denitrification:
- Where nitrogen is returned to the atmosphere
- In terrestrial and aquatic ecosystems Denitrification involves certain bacteria know as denitrifying bacteria
- Denitrifying bacteria convert nitrate back into nitrogen gas
• Human activities:
- Fossil fuels and burning organic matter release nitrogen into the atmosphere, where it forms acid rain.
- Chemical fertilizers also contain nitrogen, which escapes into the atmosphere or leaches into lake and streams.
The Phosphorus Cycle
• Necessary for life processes on plants and animals.
• Carries energy to cells
• Found in phosphate (PO4³-) rock and sediments on the ocean floor.
• Weathering:
- Releases phosphorus into soil.
- The process of breaking down rock into smaller fragments.
- Chemical weathering reacts, which causes phosphate rocks to break, down and releases phosphate soil.
- Acid participation and the chemicals released by lichens can also cause chemical weathering.
- Physical Weathering is when wind, rain, and freezing release particles of rock and phosphate into the soil.
• Decomposers:
- Organisms take up phosphorus and when they die, decomposers return phosphorus to the soil.
- The excess phosphors settle on the floor of lakes and oceans, forming sedimentary rock.
• Geologic Uplift:
- Phosphorus remains trapped for a long time until the rock layers are exposed through geologic uplift.
- Geologic uplift refers to the process of mountain building in which earths crust folds, and deeply buried rock rise and uncover.
• Human Activity:
- Commercial fertilizers and phosphate-containing detergents enter waterways and contribute phosphate to the phosphorus cycle.
- Slash and burn forest reduces phosphate levels
Section 2.3- Effects of Bioaccumulation on Ecosystems
Bioaccumulation
• Human Activity:
- Creates many harmful pollutants
- Bioaccumulation refers to the gradual build-up of pollutants in living organisms
- Biomagnifications refers to the process in which pollutants not only accumulate but become more concentrated at each trophic level
- Keystone species are species that greatly affect ecosystems health, or the reproductive abilities of species are harmed
• PCB Concentrates:
- In orcas food web
- When orcas consume food contaminated with PCBS they store some PCBs in their blubber
- When salmon (the food they eat) orcas use their bladder for energy
- These release PCDB into the system
- PCB can also affect a whole ecosystem
• Half Life:
- The time it takes for the amount of a substance to decrease by half
Persistent Organic Pollutants
• POP’S:
- Carbon-containing compounds that remain in water and soil for many years
- Chemical accumulation is measured in parts per million
• Heavy Metals:
- Metallic elements with a high dentist that are toxic to organisms at low concentrations
- Lead, cadmium and mercury
Chapter 3: Ecosystems Changing
Section 3.1- How changes Occur Naturally
How Organisms Adapt to Change
• Natural selection-
- Best adapted members of a species to survive to reproduce
- Pass this to their offspring
How Ecosystems Change Over Time
• Ecological succession:
- Changes that take place over time in the types of organisms that live in an area
- Two types:
1. Primary Succession
- No soil exist before
- On bare rock
- Wind and rain carry spores of lichens to these areas
- Lichens obtain nutrients by secreting chemicals that break down rock
- The first organisms to survive and reproduce are called pioneer species
- After a very long time, it leads to climax (mature) community
2. Secondary Succession
- Small disturbances such as a fire, happen in an ecosystem
- Already had soil and was once the home of living organisms
- The process much faster then primary since micro-organisms, insects, seeds and nutrients still exist in soil
Section 3.2- How Humans Influence Ecosystems
Sustainability
• Sustainability:
- The ability of an ecosystem to sustain ecological processed
- Land use refers to the ways we use the land around us
- Resource use is the ways we obtain our resources like wood, soil, water and minerals
• Traditional Ecological Knowledge:
- First nations’ through understanding of the plants, animals and natural occurrences in their environment
- Reflects knowledge about local climate and resources, biotic and abiotic characteristic, and animal and plant life cycles
Resource Exploitation Affect Ecosystem
Effect Example of Human Activity How ecosystems are affected
Habitat loss Humans take over natural space in the creation of cities Habitats are destroyed and no longer can support the species
Habitat fragmentation Agriculture etc. divide natural ecosystems into smaller, isolated fragments Plant pollination
Deforestation Forests are logged or cleared for human use and never replanted The # of plants and animals living in an ecosystem are reduced
Soil degradation Leave land bare so water and wind erosion remove top soil Reducing plant growth
Soil compaction Farm vehicles are grazing animals squeeze soil particles together Reduces the movement of air, water and soil organisms in soil
Contamination By-products of resource exploitation such as mining, introduce toxins Kills plants and animals
Overexploitation A resource is used or extracted until it is depleted Food webs are affected
Section 3.3- Introduced Species
Introduced Species
• Native Species:
- Plants and animals that naturally inhabit an area
• Introduced species (foreign):
- Plants and animals that have been introduced into an ecosystem by humans
- Beneficial or harmless
• Invasive Species:
- Take over a habitat of native species
- Also invade their bodies, weakening their immune system
Example: Scotch broom was introduced to BC as a garden plane. It has up to 18 000 seeds per plant, can survive drought, and fixes nitrogen in the soil, causing conditions they many native species have trouble growing in. Together with other introduced species, is competition with the keystone species Carry Oak on Vancouver Island.
Effect Harm to Native Species
Competition • Aggressive
• They easily outcompete native species for food and habitat
Predation • Introduced predators can have more impact on a prey population than native predators
• Prey may not have adaptations to escape or fight them
Disease and parasites • An invasion of parasites or disease-causing viruses and bacteria
• Can weaken the immune response of native plants and animals
Habitat alternation • Introduced invasive species can make a natural habitat unsuitable for native species
• Changing its structure or composition
Chapter 4: Atomic Theory explains the formation of compounds
Section 4.1- Atomic Theory and Bonding
Atoms
• A compound:
- A pure substance that is composed of two or more atoms combined in a specific way
• Atom:
- The smallest particle of an element that retain the properties of an element
• Atomic theory:
- Subatomic particle are the particles that make up an atom
Name Symbol Electric Charge Location in Atom Relative Mass
Proton p 1+ Nucleus 1836
Neutron n 0 Nucleus 1837
Electron e 1- Surrounding the nucleus 1
• The Nucleus:
- The center of each atom
- The electric charge is always positive
- Nuclear charge (atomic number) is the electric charge on the nucleus and is found containing the amount of electrons
• The Periodic Table:
- Each element is listed according to their atomic number
- Each row is called a period
- Each column (top and bottom) is called a group or family
- Metals on the left and in the middle of the table
- Elements in the same family have similar properties:
a) Alkali metals (1)- very reactive metals
b) The alkali earth metals (2)- somewhat reactive metals
c) The halogens (17)- very reactive non-metals
d) The noble gases (18)- very un-reactive heasous non-metals
The Periodic Table and Ion Formation
• Ions:
- When atoms gain or lose electrons the become electrically charged particles called ions
- Metals lose electrons to form positive electrons
- Non-metals gain electrons to for negative electrons
• Multivalent:
- Can from ions in more than one way
• Bohr Diagrams:
- A diagram that shows how many electrons are in each shell surrounding the nucleus
- Electrons organized in shells
First shell- 2 electrons
Second shell- 8 electrons
- When this shell is full it is called a stable octet
- Valence shell is the outermost shell of electrons and those electrons are called valence electrons
Forming Compounds
• Ionic bonding:
- Contains a positive ion (metal) and a negative ion
- One or more electrons are transfers from each atom of the metal to each atom of the non-metal
- The metal atoms lose electrons forming cations
- The non-metal atoms gain electrons forming anions
• Covalent bonding:
- The atoms of a non-metal share electrons with other non-metals atoms
- An unpaired electron from each atom will pair together forming a covalent bond sometimes called bonding pairs
Lewis Diagrams
- Illustrates chemical bonding by showing only an atom’s valence electrons and it’s chemical symbol
- Dots represent electrons are placed around the elements symbols
- Electron dots are placed singly until the fifth electron is reached, then they are paired
- Positive ions- one electron dot is removed from the valence shell for each positive charge of the ion
- For negative ion- one electron dot is added to each valence shell for each negative charge of an ion
Section 4.2- Names and Formulas
Naming and Writing Ionic Compounds
• Naming:
- The first part of the name is the positive ion (a metal
- The second part is the negative ion (non-meals) which always ends with “-ide”
Example: lead sulphide
• Writing formulas:
1. Indentify the chemical symbol for each ion and its charge
2. Determine the total charges needed to balance the positive and negative charges of each ion
3. Note the ratio of positive to negative ions
4. Use these subtracts to write the chemical formula
Naming and Writing Ionic Compounds
• Writing Formulas:
1. Indentify each ion and its charge
2. Determine the total charges needed to balance positive with negative
3. Note the ratio of positive ions to negative ions
4. Use subscripts to write the formula
Multivalent Metals
• Can form two or more positive ions with different ionic charges
• Has roman numerals
Metal Ion Charge Roman Numeral
1+ I
2+ II
3+ III
2+ IV
5+ V
6+ VI
7+ VII
Polyatomic Ions
- Composed of more than one type of atom joined by a covalent bonds
- Have special names assigned to them
- (Need to look at a table)
Binary Covalent Compound
• Binary covalent compounds:
- Contains two nonmetals elements joined together by one or more covalent bonds
- Prefixes indicate the number of atoms of each element that appear in the formula
• Writing names”
1. Name the left most element in the formula first
2. Name the second element making sure the element name end with the suffix ide
3. Add the prefix to each elements name to indicate the number of atoms of each element in the compound
**If the first element has only one atom, do not add a prefix
Prefix Number
Mono- 1
Di- 2
Tri- 3
Tetra- 4
Penta- 5
Hexa- 6
Hepta- 7
Octa- 8
Nona- 9
Deca- 10
Example:
- P4010 tertaphosphrous decaoxidene ne can
Section 4.3- Chemical Equations
Chemical change
• Reactants and Products:
- Involves the conversion of pure substance called reactants into other pure substances called products with different properties from the reactants
- One or more chemical changes that occur at the same time are called chemical reaction
• How it is represented:
- By suing a chemical equation
- May be written in word or chemical symbols
- The symbols for states of matter are solid (s), gas (g) and liquids (l)
Conservation of Mass
• Law:
- Atoms are neither destroyed nor produced in a chemical reaction
- The total mass of the products is always equal to the total mass of the reactants
Writing and Balancing Equations
• Steps:
1. Write a word equation: provides the names of the reactants and products
Example: methane +oxygen water + carbon dioxide
2. Write a Skelton equation (replaces the names of the reactant s and products in a word equation with formulas) THIS IS NOT BALANCED!
Example: CH4 + 02 H20 + CO2
3. Write a balanced equation: shows the identities of each pure substance involved in the reaction. Uses lowest number coefficients. What you start with you must end with!!!
Example: CH4 +2O2 2H20 + CO2
Chapter 5: Compounds are classified in different ways
Section 5.1: Acids and Base
Acids and Bases
• pH Scale:
- A number scale for measuring how acidic or basic a solution is.
- Less than 7 acidic
- More than 7 basic
- pH of 7 neutral (neither acidic or basic)
pH values of common substances
• Acids:
- Chemical compounds that produce a solution with a pH of less than 7 when they dissolve in water.
- Taste sour, will burn you skin, they corrode metals, conduct electricity.
• Bases:
- Compounds that produce a solution of pH of more than 7 when dissolve in water.
- Taste bitter, feel slippery, many will burn your skin, no reaction to meals, conduct electricity.
pH Indicators
• pH Indicators Used For:
- Chemicals that change color depending on the pH of the solution they are placed in.
- Blue litmus paper turns red in an acidic solution.
- Red litmus paper turns to blue in a basic solution.
- Phenolphthalein, bromothymol blue, indigo carmine, methyl orange and methyl red are other common ph indicators.
Naming Acids and Bases
• Acids:
- Chemical formulas are usually written with an H on the left side of the formula.
- If no state of matter is given, the name may be given beginning with hydrogen, as in hydrogen chloride.
- If acids is shown as being aqueous as in HCI(aq), a different name may be used that ends in “-ic acid” as in hydrochloric acid.
• Names of Acids:
- Names that begin with hydrogen and end with the suffix “-ate” can be changed by dropping “hydrogen” from the name and changing the suffix to –ic
Example: H2CO3- hydrogen carbonate
• Bases:
- They are usually written with an OH on the right side of the formula.
- Common names of bases include sodium hydroxide and magnesium hydroxide.
Section 5.2: Salts
Acid Base Neutralization
• Neutralization (acid base):
- acid and a base react to form a salt and water
Example: HCI + NaOH NaCI + H2O
Metals Oxides and Non-Metal Oxides:
• Metal Oxides:
- Contains a metal chemically combined with oxygen.
- The solution becomes basic
Example: Na2O(s) + H2O 2NaOH(aq) (a base Sodium hydroxide
• Non-Metals Oxides
- Contains a non-metal chemically combined with oxygen.
- The solution become acidic
Example: CO2(g) + H2O(l) H2CO3(aq) Carbonic acid
Acids, Metals and Carbonates
• Acids and Metals:
- When metals react with acids to produce salt, they usually release hydrogen gas
- The most reactive metal are the alkali metals and the alkaline earth metals.
- The bottom of the columns reacts most vigorously.
• Carbonates:
- React with acids to produce salts.
- Much of the carbon dioxide on the surface of the earth is trapped in rocks, such as limestone, dolomite, and calcite.
- Carbonates help to neutralize acids.
Section 5.3: Organic Compounds
Organic Compounds
• Organic and Inorganic Compounds:
- Organic compounds are any compounds that contain carbon (with a few expectations)
- Carbon in organic compounds forms four bonds.
- To recognize a compound as organic: Look for an indication of the presence of the presence of carbon in its name, chemical formula or diagram.
- Inorganic compounds include compounds that generally don’t contain carbon and also a few exceptions to the organic classification (i.e. carbon dioxide, carbon monoxide, and ionic carbonates).
Hydrocarbons
• A hydrocarbon:
- An organic compound that contains only the elements carbon and hydrogen (simples is methane)
Alcohols
• Alcohol:
- One of a kind organic compound that contains C. H, and O.
- Many types such as methanol, ethanol and isopropyl alcohol.
- A solvent is a liquid that can dissolve other substances.
Chapter 6: Chemicals Reactions
Section 6.1- Types of Chemical Reactions
Chemical Reactions
• Six main types:
- Synthesis
- Decomposition
- Single replacement
- Double replacement
- Neutralization (acid, base)
- Combustion
Synthesis
• Synthesis (combination) reactions:
- Two or more reactants (A and B) combine to produce a singe product (AB). A + B AB
Decomposition
• Decomposition reaction:
- A compound is broken down into smaller compounds or separate elements.
- The reverse of a synthesis reaction.
Example: compound element + element
AB A + B
Single Replacement
• Single Replacement reaction:
- A reactive element (a metal or non-metal) and a compound react to produce another element and another compound react to produce another element and another compound.
- One of the elements in the compound is replace by anther element.
- The element that is replaced could be a metal or a non-metal.
Example: element + compound element + compound
A + BC B + AC where A is a metal OR
A + BC C + BA where A is a non-metal
Double Replacement
• Double Replacement Reaction:
- Usually involves two ionic solutions that react to produce two their ionic compounds.
- One of the compounds forms a precipitate, which is an insoluble solid that forms a solution.
Example: ionic solution + ionic solution ionic solution + ionic solution
AB(aq) + CD(aq) AD(aq) + CB(s)
Neutralization (acid-base)
• Neutralization (acid-base) reaction:
- When an acid and a base are combined, they will neutralize each other.
- An acid and a base react to form a salt and water.
Example: acid + base salt + water
HX + MOH MX + H20 (X= negative ion, M= positive ion)
Combustion
• Combustion reaction:
- The rapid reaction of a compound or element with an oxygen to form an oxide and produce heat.
Example: hydrocarbon + oxygen carbon dioxide + water
Section 6.2- Factors Affecting Chemical Reactions
Rate of Reaction
• Rate of reaction:
- How quickly or slowly reactants turn into products.
- A reaction that takes a long time has a low reaction rate.
- A reaction that occurs quickly has a high reaction rate.
- A rate describes how quickly or slowly a change occurs.
• Factors affected rate of reaction:
- Temperature
- Concentration
- Surface Area
- Catalyst
Temperature
• Increasing + Higher Temperature:
- Causes the particles (atoms or molecules) of the reactants to move more quickly so that they collide with each other more frequently and with more energy.
- The higher the temperature the greater the rate of reaction.
• Decreasing + Lower Temperature:
- If you decrease temperature the particles move more slowly, colliding less frequently and with less energy.
- The rate of reaction decreases.
Concentration:
• Greater Concentration:
- if a greater concentration of reactant atoms and molecules is present, there is a greater chance that collisions will occur among them.
- More collisions mean a higher reaction rate.
- Increasing concentration of the reactants usually results in a higher reaction rate.
- When you blow on a campfire, you are increasing the concentration of oxygen near the flames,
• Lower Concentration:
- There is less chance for collision between particles.
- Decreasing the concentration of the reactants results in a lower reaction rate.
Surface Area
• For the same mass:
- Many small particles have a greater total SA than one large particle.
- The more surface contact between reactants, the higher the rate of reaction.
- The less surface contact, the lower the reaction rate.
Catalyst
• A catalyst:
- Substance that speeds up the rate of a chemical reaction without being used in the reaction itself.
- Reduce the amount of energy required to break and form bonds during chemical reaction.
- A reaction can proceed although less energy is added during the reaction.
• Enzymes
- Catalysts that allow chemical reactions to occur ate relatively low temperatures within the body.
- Large organic molecules, usually proteins, which speed up reaction in living cells.
- Each enzyme in your body is specialized to perform its own function.
Chapter 7: The Atomic Theory
Section 7.1- Atomic Theory, Isotopes and Radioactive Decay
Radioactivity
• Radioactivity:
- The release of high-energy particles and rays of energy from a substance as a result of changes in the nuclei of its atoms.
- Radiation refers to high-energy rays and particles emitted by radioactive sources.
- Includes radio waves, microwaves, infrared rays, visible light and ultraviolent rays
- Light is one form of radiation that is visible to humans.
Isotopes:
• Isotopes:
- Different atoms of a particular element that have the same number of protons but different numbers of neutrons.
- All isotopes of an element have the same atomic number (protons), however, since the number of neutrons differs, the mass number and atomic mass differ from one isotope to the next.
• Mass number:
- An integer (whole #) that represents the sum of an atom’s protons and neutrons.
Mass number = atomic number + number of neutrons
Number of protons = mass number – atomic number
• Representing Isotopes:
- Includes the chemical symbol, atomic number and the mass number.
- The mass number is written as a subscript (above) on the left of the symbol.
- The atomic number is written as a subscript (below) on the left.
Radioactive Decay
• Radioactive Decay:
- The process in which unstable nuclei lose energy by emitting radiation.
- By emitting radiation, atoms of one kind of element can change into atoms of another element.
- Radioisotopes are natural or human-made isotopes that decay into other isotopes, releasing radiation.
- Three types of radiation: alpha, beta and gamma.
Property Alpha Radiation Beta Radiation Gamma Radiation
Symbol 42He or 42a 0-1b or 0-1e 00y
Composition Alpha particles Beta particles High-energy Radiation
Description Helium nuclei Electrons High energy rays
Charge 2+ 1- 0
Relative Penetrating Blocked by paper Blocked by metal foil Partly/completely blocked
Power Or concrete By lead
Alpha Radiation:
• Alpha particles:
- Positively charged atomic particles that are much more massive that either beat and gamma radiation.
- Same combination of particles as the nucleus of a helium atom.
- Alpha particle has a mass number of 4 and an atomic number of 2, two protons and two neutrons.
- Has an electric charge of 2+.
- Relatively slow moving compared with other types of radiation.
- Not very penetrating- a single sheet of paper stops alp ha particles.
• Alpha decay:
- The emission of an alpha particle from a nucleus.
Beta Radiation:
• Beta particle:
- An electron that has a mass number of 0.
- Has an electric charge of 1-.
- Beat particles are lightweight and fast moving that have a greater penetrating power than alpha particles.
- A thin sheet of aluminum foil can block beta particles.
• Beat Decay:
- A neutron changes into a proton and an electron.
- Proton remains in the nucleus while the electron shoots out from the nucleus with a lot of energy.
- The atomic number increases by one- it has become an atom of the next higher element.
- The mass number does not change.
Gamma Radiation
• Gamma Radiation:
- Consists of rays of high-energy, short-wavelength radiation.
- Have almost no mass and no charge. The release of gamma radiation does not change the atomic number or the mass number of a nucleus.
- Highest energy form of electromagnetic radiation.
• Gamma Decay:
- Results from a redistribution of energy within the nucleus.
- A gamma ray is given off as the isotope changes from high-energy to a lower energy state.
Section 7.2- Half-Life
Carbon Dating
• Radiocarbon dating:
- The process of determining the age of an abject by measuring the amount of carbon-14 remaining in that object.
- Carbon isotopes include carbon-23 and carbon-14.
- When an organism is alive the ratio of carbom-14 atoms to carbon-12 atoms in the organism remains nearly constant.
• The Rate of Radioactive Decay:
- Half life- is a constant for any radioactive isotope and is equal to the time required for a half the nuclei in a sample to decay.
• Using a Decay Curve:
- A decay curve is a curved line on a graph that shows the rate at which radioisotopes decay.
Common Isotope Pairs
• Parent and Daughter Isotope
- The isotope that undergoes radioactive decay is called the parent isotope.
- The stable products of radioactive decay are called the daughter isotope.
- The production of a daughter isotope can be a direct reaction or the result of a series of decays.
Parent Daughter Half Life of Parent Effective Dating Range
Carbon-14 Nitrogen-14 5730 Up to 50 000
Uranium-235 Lead-207 710 million > 10 million
Potassium-40 Argon-40 1.3 billion 10 000 to 3 billion
Uranium-238 Lead-206 4.5 billion > 10 million
Theorium-235 Lead-208 14 billion > 10 million
Rubidium-87 Strontium-87 47 billion > 10 million
The Potassium-40 Clock
• How it Works:
- It uses radioisotopes, specifically potassium-40 and argon-40, to determine Earths age.
- When rock is produced from lava, all the gases (including potassium-40) in the molten rock are driven out, this process sets the potassium radioisotope clock to zero.
Section 7.3- Nuclear Reactions
Nuclear Fission
• Nuclear Fission:
- The splitting of a big nucleus into two smaller nuclei, subatomic particles and energy.
- Heavy nuclei are unstable due to repulsive forces between the many protons.
- To increase stability, atoms with heavy nuclei may split into atoms with lighter nuclei.
- Fission is accompanied by a very large release of energy.
- 4He2 +14N7 17O8 + 1H1
• Nuclear Fission of Uranium-235:
- When a nucleus of uranium-235 is stuck by or bombarded with a neutron, the nucleus absorbs the neutron.
- Result, the mass number of the nucleus increases by one.
- Because the number of protons had not changed, this is still an atom of uranium (just different isotope.)
- When a uranium nucleus undergoes fission, they release neutrons, which trigger more fission reactions.
Nuclear Fusion
• Nuclear Fusion:
- The processes in which two low mass nuclei join together to make a more massive nucleus.
- It occurs at the core of the Sun and other stars, where there is a lot of pressure and high enough temperature to force isotopes of hydrogen to collide with great force.
- 2H1 + 3H1 4H2 + 1n0 + energy
- We don not currently have the technology to extract energy from fusion reactions.
Comparing Nuclear Fission and Fusion:
Nuclear Fission Nuclear Fusion
Beginning Heavy unstable nuclei split apart in two smaller nuclei. Two lightweight nuclei join together to form a heavier nucleus.
Releases Unstable nuclei release a huge amount of energy when they split. Lightweight nuclei release a huge amount of energy when they join.
Energy Heavy nuclei- don’t release energy Lightweight nuclei- will not release energy
Products Produce daughter products that are radioactive. No not produce products that are radioactive.
Technologies Many countries generate some electrical power through fission reactions. No commercial fusion reactors are in use or under construction.
Research Try to produce environmentally friendly nuclear power generation Try to produce a fusion nuclear reactor.
Used Used in modern nuclear weapons Used in modern nuclear weapons to generate most of the energy released in the blast.
Nuclear Equation:
• A nuclear Equation:
- A set of symbols that indicates changes in the nuclei of atoms during a nuclear reaction.
• Rules:
1. The sum of the mass numbers on each side of the equation stays the same.
2. The sum of the charges (represented by atomic number) on each side of the equation stays the same.
UNIT 1 Sustaining Earth’s Ecosystem
Chapter 1: Biomes and Ecosystems
• Section 1.1- Biomes
• Section 1.2- Ecosystems
Chapter 2: Energy Flow and Nutrient Cycles
• Section 2.1- Energy Flow in Ecosystems
• Section 2.2- Nutrient Cycles in Ecosystems
• Section 2.3- Effects of Bioaccumulation on Ecosystems.
Chapter 3: Ecosystems Changing
• Section 3.1- How changes Occur Naturally
• Section 3.2- How Humans Influence Ecosystems
• Section 3.3- Introduced Species
UNIT 2 Chemical Reactions and Radioactivity
Chapter 4: Atomic Theory explains the formation of compounds
• Section 4.1- Atomic Theory and Bonding
• Section 4.2- Names and Formulas
• Section 4.3- Chemical Equations
Chapter 5: Compounds are classified in different ways
• Section 5.1- Acids and Bases
• Section 5.2- Salts
• Section 5.3- Organic Compounds
Chapter 6: Chemicals Reactions
• Chapter 6.1- Types of Chemical Reactions
• Section 6.2- Factors Affecting Chemical Reactions
Chapter 7: The Atomic Theory
• Section 7.1- Atomic Theory, Isotopes and Radioactive Decay
• Section 7.2- Half-Life
• Section 7.3- Nuclear Reactions
UNIT 3 Motion
Chapter 8: Average Velocity
• Section 8.1- The Language of Motion
• Section 8.2- Average Velocity
Chapter 9: Acceleration
• Section 9.1- Describing Acceleration
• Section 9.2- Calculating Acceleration
UNIT 4 Energy Transfer in Natural Systems
Chapter 10: The Kinetic Molecular Theory
• Section 10.1- Temperature, Thermal Energy and Heat
• Section 10.2- Energy Transfer in the Atmosphere
Chapter 11: Climate Change
• Section 11.1- Natural Causes of Climate Change
• Section 11.2- Human Activity and Climate Change
Chapter 12: Thermal Energy transfer Drives Plate Tectonics
• Section 12.1- Evidence for Continental Drift
• Section 12.2- Features of Plate Tectonics
Chapter 1: Biomes and Ecosystems
Section 1.1- Biomes
Abiotic and Biotic
• Biotic- living components:
- Organisms
- Plants, animals, fungi and bacteria
- Interact with each other and with the physical and chemical environment in which they live in
• Abiotic- non- living components:
- Sunlight, soli, moisture and temperature
Biome
• Includes large regions that have similar biotic components:
- Similar temperature and amount of rainfall
- There are 8 terrestrial (land based) biomes
1. Boreal Forest
2. Desert
3. Grassland
4. Permanent Ice
5. Temperate Deciduous Forest
6. Temperate Rainforest
7. Tropical Rainforest
8. Tundra
Factors That Influence Biomes
• Temperature and Precipitation:
- Precipitation- rain, snow, mist and fog
- Most important abiotic factors that influence the characteristics of biomes
- Animals and plants can only survive in specific temperatures and the amount of precipitation
- Graph- y axis: annual precipitation and x axis: find the intersection with the average annual temperature
• Latitude:
- Abiotic factor that affects the temperature and precipitation
- Distance measured in degrees north or south from the equator
- Tropical zone: is close to equator, it receives more direct sunlight and has warm temps.
- Sun rays less intense farther away from the equator, the temp. In these zones are lower that they are at the equator.
- At the equator- the direct sunlight heats moist air, which rises, cools in the upper atmosphere and falls on earth as rain
- Land or oceans on the equator receive greatest amount of precipitation
• Elevation:
- The height of a land mass above sea level
- Affects temperature because atmosphere is thinner at a higher elevation which means it retains less heart
- Windward side of a mountain: clouds filled with moisture rise and cool then release rain or snow
- Leeward side- (sheltered by the wind) the air warms again, which allows it to absorb water creating a dry land area
• Ocean Currents:
- Also and abiotic factor that affects temp and precipitation
- Makes biome warmer and wetter
Climatographs
• Climate and Climotographs:
- Climate: average pattern of weather conditions that occur in a region
- Climatograph: a graph of climate data usually obtained over 30 years from local weather observations
- Month of the years is shown is shown on the horizontal axis
- The average temp is shown on the right vertical axis
- The average propitiations is shown on the left vertical axis
Adaptations and Biomes
• Adaption’s:
- Characteristics that enable organisms to better survive and reproduce. There are 3 types:
a) Structural adaptation- physical feature of an organisms having a specific function that contributes to the survival of the organism
Example: pine trees are cone-shaped and therefore get rid of snow.
Example: Arctic fox has thick, white coat in the winter and a brownish-grey one in the simmer for camouflage.
b) Physiological Adaptation- physical or chemical event that occurs within the body of the organism that enables survival.
Example: wolves can contain a constant body temperature no matter the weather conditions.
c) Behavioral Adaptations- what an organism does to survive in the unique conditions of its environment. (Feeds, mates, cares for young, migrate, hibernate or escape from predators.)
Example: the owl lines his nest with grass, which keeps it cool during the day and warm at night.
The Biomes:
1. Tundra • Located in the upper northern hemisphere
• Very cold and dry
• Permanently frozen soil (permafrost)
• Plants are short and there are few trees
• Animals have compact bodies and shorter legs and ears which reduce heat loss
2. Boreal Forest • Found in the far north
• Below freezing half the year
• Mainly coniferous (cone-bearing) trees
3. Temperate Deciduous Forest • Located in temperate regions- mostly eastern North American, eastern Asia and Europe
• Trees lose their leaves in winter (tall tress)
• Large seasonal changes with four distinct seasons
4. Temperate Rainforest • Found along coastlines where oceans winds drops large amounts of moisture
• Coast of Chile, BC, New Zealand, part of Australia
• Cool and very wet (fog which provides moisture and rainfall)
• Allows trees (mainly evergreens) to grow very tall
5. Grassland • Occurs in temperate and tropical regions
• Canada, North America, Russia, Africa, South America, northern Australia
• Covered with grasses that have deep roots, which are well adapted to droughts
• Limited rainfall and land is mainly flat
• Large grazing animals
6. Tropical Rainforest • Found in wide band around the equator
• Northern South America, Central America, central Africa and southeast Asia
• Wet and warm all year around
• Allows the growth of a dense canopy of tall tress
• Hass the greatest diversity of animals but few large a mammals
7. Desert • Occur in temperate and tropical regions
• Days are hot and nights are cold
• Rainfall is minimal and plans and animals are adapter to reduce water loss
• Reptiles are common and have thick skin and scales
8. Permanent Ice • Includes the polar land masses and large polar ice caps
• Arctic, Greenland and Antarctica
• The few animals that live there are well insulated against the extreme cold
Section 1.2- Ecosystems
Parts of an Ecosystem
• Ecosystem
- Has abiotic factors- oxygen, water, nutrients, light and soil
- Biotic factors- plants and animals, microorganisms.
- Within an ecosystem is a habitat which is a place in which an organism lives
Abiotic Interactions in Ecosystems
• Interactions:
- Organisms have special roles-or niches in their ecosystem
- The way it contributes to and fits into its environment
- Biotic interactions are structured form smallest to largest in and ecological hierarchy
a) A species: is a group of closely related organisms that can reproduce with one another
b) Population- all the members of a species within an ecosystem
c) Community- populations of a different species that interact in a specific ecosystem
Biotic Interactions in Ecosystems
• Symbiosis:
- The interaction of two different organisms that live in close association
- Communalism, mutualism, parasitism, competition, predation, and mimicry
Interaction Result Example
Commensalism One Organism benefits and the other is neither helped nor harmed. Barnacles attach to whales and are transported to new locations in the ocean.
Mutualism Both organisms benefit and sometimes neither species can survive without the other. In lichen, the alga produces sugars and oxygen for the fungus, which provides carbon dioxide and water for the alga.
Parasitism One species benefits and another is harmed. Hookworms attach to the gut wall and obtain nourishments from their host’s blood.
Competition Organisms require the same resource (i.e. food) in the same place at the same time. Spotted knapweed release chemicals into the soil, which prevents the growth of other plants.
Predation One organism (the predator) eats all or part of another organism (the prey). Cougars have sharp, pointed teeth to catch prey.
Mimicry A prey animal mimics another species that is dangerous or tastes bad to avoid being eaten. Viceroy butterflies look like bitter-tasting monarch butterflies and are avoided by predators.
Chapter 2: Energy Flow and Nutrient Cycles
Section 2.1- Energy Flow in Ecosystems
• Energy Flow:
- Producers: plants that produce food in the form of carbohydrates during photosynthesis
- Consumer: a insects that eats the plant
• Dead organisms:
- Decomposition: the breakdown of organic wastes and dead organism
- Biodegradation: when living organisms carry out decomposition
a) Detrivores, such as small insects, earthworms, bacteria and fungi, obtain energy and nutrients by eating dead plants and animals, as well as animal waste
b) Decomposers, such as bacteria and fungi, change wastes and dead organisms into nutrients that can be used by plants and animals
Food Chains and Webs
• Food Chains
- Show the flow of energy from plant to animal and from animal to animal
- Each step in a food chain is called a trophic level
- Detrivores: consumers that obtain energy at every trophic level and nutrients by eating small dead stuff
- Herbivores: primary consumers that eat plants
- Carnivores: secondary consumers that eat primary consumer
Trophic
Level Organism Energy Source Example
1st Primary producer Obtain energy from the sun Grass, algae
2nd Primary consumer Obtain energy from primary producers Grasshoppers, krill
3rd Secondary consumer Obtain energy from primary consumer Frogs, crabs
4th Tertiary consumer Obtain energy from secondary consumers Hawks, sea otters
• Food webs:
- Interconnected food chains
- Animals are in several food chains because they eat or get eaten by several organisms
• Food Pyramid:
- Shows the loss of energy from one trophic level to another
- Not all energy in incorporated into the consumers tissues
- Between 80 and 90% of energy is used for chemical reactions and is lost as heat
- Ecosystems can support fewer organisms at higher trophic levels, as less energy reaches these levels
Section 2.2- Nutrient Cycles in Ecosystems
The Carbon Cycle
• Cycled through living and decaying organisms, the atmosphere, bodies of water and soil and rock
• Photosynthesis:
- It is a chemical reaction that converts solar energy into chemical energy by an important process in which carbon and oxygen cycle through the ecosystem
- Energy (sunlight) + 6CO2 + 6H2 * C6H1206 + 602
• Cellular Respiration:
- Plants and animals breath out carbon dioxide back into the atmosphere by converting carbohydrates and oxygen into carbon dioxide and water
- C6H1206 (carbohydrates) + 602 * 6CO2 +6HO2 + 6H2O + energy
• Decomposition:
- Breaks down dead organic matter
- Examples of decomposers are bacteria and fungi that convert organic molecules back into carbon dioxide, which then is released into the atmosphere
• Ocean Process and Human Activity:
- Ocean process dissolves carbon dioxide that is stored in oceans
- Human activities are burning foil and clearing land which both release carbon quickly
The Nitrogen Cycle
• Component of DNA and proteins, which are essential for the life, processes that take place inside the cell.
• Most nitrogen is stored in the atmosphere (N2 nitrogen gas)
• Nitrogen Fixation:
- The process in which nitrogen gas is converted into compounds that conation nitrate or ammonium which are useful for plants
- Nitrogen fixation occurs in: atmosphere, soil and in water bodies
• Nitrification an Uptake:
- In Nitrification ammonium (NH4+) is converted into nitrate (NO3-)
- Takes place in two stages
- First stage: certain species of nitrifying bacteria convert ammonium into nitrate.
- Second stage: different species of nitrifying bacteria convert nitrite into nitrate
- The uptake is where useable forms of nitrogen are taken up by plant roots and included into plant proteins
• Denitrification:
- Where nitrogen is returned to the atmosphere
- In terrestrial and aquatic ecosystems Denitrification involves certain bacteria know as denitrifying bacteria
- Denitrifying bacteria convert nitrate back into nitrogen gas
• Human activities:
- Fossil fuels and burning organic matter release nitrogen into the atmosphere, where it forms acid rain.
- Chemical fertilizers also contain nitrogen, which escapes into the atmosphere or leaches into lake and streams.
The Phosphorus Cycle
• Necessary for life processes on plants and animals.
• Carries energy to cells
• Found in phosphate (PO4³-) rock and sediments on the ocean floor.
• Weathering:
- Releases phosphorus into soil.
- The process of breaking down rock into smaller fragments.
- Chemical weathering reacts, which causes phosphate rocks to break, down and releases phosphate soil.
- Acid participation and the chemicals released by lichens can also cause chemical weathering.
- Physical Weathering is when wind, rain, and freezing release particles of rock and phosphate into the soil.
• Decomposers:
- Organisms take up phosphorus and when they die, decomposers return phosphorus to the soil.
- The excess phosphors settle on the floor of lakes and oceans, forming sedimentary rock.
• Geologic Uplift:
- Phosphorus remains trapped for a long time until the rock layers are exposed through geologic uplift.
- Geologic uplift refers to the process of mountain building in which earths crust folds, and deeply buried rock rise and uncover.
• Human Activity:
- Commercial fertilizers and phosphate-containing detergents enter waterways and contribute phosphate to the phosphorus cycle.
- Slash and burn forest reduces phosphate levels
Section 2.3- Effects of Bioaccumulation on Ecosystems
Bioaccumulation
• Human Activity:
- Creates many harmful pollutants
- Bioaccumulation refers to the gradual build-up of pollutants in living organisms
- Biomagnifications refers to the process in which pollutants not only accumulate but become more concentrated at each trophic level
- Keystone species are species that greatly affect ecosystems health, or the reproductive abilities of species are harmed
• PCB Concentrates:
- In orcas food web
- When orcas consume food contaminated with PCBS they store some PCBs in their blubber
- When salmon (the food they eat) orcas use their bladder for energy
- These release PCDB into the system
- PCB can also affect a whole ecosystem
• Half Life:
- The time it takes for the amount of a substance to decrease by half
Persistent Organic Pollutants
• POP’S:
- Carbon-containing compounds that remain in water and soil for many years
- Chemical accumulation is measured in parts per million
• Heavy Metals:
- Metallic elements with a high dentist that are toxic to organisms at low concentrations
- Lead, cadmium and mercury
Chapter 3: Ecosystems Changing
Section 3.1- How changes Occur Naturally
How Organisms Adapt to Change
• Natural selection-
- Best adapted members of a species to survive to reproduce
- Pass this to their offspring
How Ecosystems Change Over Time
• Ecological succession:
- Changes that take place over time in the types of organisms that live in an area
- Two types:
1. Primary Succession
- No soil exist before
- On bare rock
- Wind and rain carry spores of lichens to these areas
- Lichens obtain nutrients by secreting chemicals that break down rock
- The first organisms to survive and reproduce are called pioneer species
- After a very long time, it leads to climax (mature) community
2. Secondary Succession
- Small disturbances such as a fire, happen in an ecosystem
- Already had soil and was once the home of living organisms
- The process much faster then primary since micro-organisms, insects, seeds and nutrients still exist in soil
Section 3.2- How Humans Influence Ecosystems
Sustainability
• Sustainability:
- The ability of an ecosystem to sustain ecological processed
- Land use refers to the ways we use the land around us
- Resource use is the ways we obtain our resources like wood, soil, water and minerals
• Traditional Ecological Knowledge:
- First nations’ through understanding of the plants, animals and natural occurrences in their environment
- Reflects knowledge about local climate and resources, biotic and abiotic characteristic, and animal and plant life cycles
Resource Exploitation Affect Ecosystem
Effect Example of Human Activity How ecosystems are affected
Habitat loss Humans take over natural space in the creation of cities Habitats are destroyed and no longer can support the species
Habitat fragmentation Agriculture etc. divide natural ecosystems into smaller, isolated fragments Plant pollination
Deforestation Forests are logged or cleared for human use and never replanted The # of plants and animals living in an ecosystem are reduced
Soil degradation Leave land bare so water and wind erosion remove top soil Reducing plant growth
Soil compaction Farm vehicles are grazing animals squeeze soil particles together Reduces the movement of air, water and soil organisms in soil
Contamination By-products of resource exploitation such as mining, introduce toxins Kills plants and animals
Overexploitation A resource is used or extracted until it is depleted Food webs are affected
Section 3.3- Introduced Species
Introduced Species
• Native Species:
- Plants and animals that naturally inhabit an area
• Introduced species (foreign):
- Plants and animals that have been introduced into an ecosystem by humans
- Beneficial or harmless
• Invasive Species:
- Take over a habitat of native species
- Also invade their bodies, weakening their immune system
Example: Scotch broom was introduced to BC as a garden plane. It has up to 18 000 seeds per plant, can survive drought, and fixes nitrogen in the soil, causing conditions they many native species have trouble growing in. Together with other introduced species, is competition with the keystone species Carry Oak on Vancouver Island.
Effect Harm to Native Species
Competition • Aggressive
• They easily outcompete native species for food and habitat
Predation • Introduced predators can have more impact on a prey population than native predators
• Prey may not have adaptations to escape or fight them
Disease and parasites • An invasion of parasites or disease-causing viruses and bacteria
• Can weaken the immune response of native plants and animals
Habitat alternation • Introduced invasive species can make a natural habitat unsuitable for native species
• Changing its structure or composition
Chapter 4: Atomic Theory explains the formation of compounds
Section 4.1- Atomic Theory and Bonding
Atoms
• A compound:
- A pure substance that is composed of two or more atoms combined in a specific way
• Atom:
- The smallest particle of an element that retain the properties of an element
• Atomic theory:
- Subatomic particle are the particles that make up an atom
Name Symbol Electric Charge Location in Atom Relative Mass
Proton p 1+ Nucleus 1836
Neutron n 0 Nucleus 1837
Electron e 1- Surrounding the nucleus 1
• The Nucleus:
- The center of each atom
- The electric charge is always positive
- Nuclear charge (atomic number) is the electric charge on the nucleus and is found containing the amount of electrons
• The Periodic Table:
- Each element is listed according to their atomic number
- Each row is called a period
- Each column (top and bottom) is called a group or family
- Metals on the left and in the middle of the table
- Elements in the same family have similar properties:
a) Alkali metals (1)- very reactive metals
b) The alkali earth metals (2)- somewhat reactive metals
c) The halogens (17)- very reactive non-metals
d) The noble gases (18)- very un-reactive heasous non-metals
The Periodic Table and Ion Formation
• Ions:
- When atoms gain or lose electrons the become electrically charged particles called ions
- Metals lose electrons to form positive electrons
- Non-metals gain electrons to for negative electrons
• Multivalent:
- Can from ions in more than one way
• Bohr Diagrams:
- A diagram that shows how many electrons are in each shell surrounding the nucleus
- Electrons organized in shells
First shell- 2 electrons
Second shell- 8 electrons
- When this shell is full it is called a stable octet
- Valence shell is the outermost shell of electrons and those electrons are called valence electrons
Forming Compounds
• Ionic bonding:
- Contains a positive ion (metal) and a negative ion
- One or more electrons are transfers from each atom of the metal to each atom of the non-metal
- The metal atoms lose electrons forming cations
- The non-metal atoms gain electrons forming anions
• Covalent bonding:
- The atoms of a non-metal share electrons with other non-metals atoms
- An unpaired electron from each atom will pair together forming a covalent bond sometimes called bonding pairs
Lewis Diagrams
- Illustrates chemical bonding by showing only an atom’s valence electrons and it’s chemical symbol
- Dots represent electrons are placed around the elements symbols
- Electron dots are placed singly until the fifth electron is reached, then they are paired
- Positive ions- one electron dot is removed from the valence shell for each positive charge of the ion
- For negative ion- one electron dot is added to each valence shell for each negative charge of an ion
Section 4.2- Names and Formulas
Naming and Writing Ionic Compounds
• Naming:
- The first part of the name is the positive ion (a metal
- The second part is the negative ion (non-meals) which always ends with “-ide”
Example: lead sulphide
• Writing formulas:
1. Indentify the chemical symbol for each ion and its charge
2. Determine the total charges needed to balance the positive and negative charges of each ion
3. Note the ratio of positive to negative ions
4. Use these subtracts to write the chemical formula
Naming and Writing Ionic Compounds
• Writing Formulas:
1. Indentify each ion and its charge
2. Determine the total charges needed to balance positive with negative
3. Note the ratio of positive ions to negative ions
4. Use subscripts to write the formula
Multivalent Metals
• Can form two or more positive ions with different ionic charges
• Has roman numerals
Metal Ion Charge Roman Numeral
1+ I
2+ II
3+ III
2+ IV
5+ V
6+ VI
7+ VII
Polyatomic Ions
- Composed of more than one type of atom joined by a covalent bonds
- Have special names assigned to them
- (Need to look at a table)
Binary Covalent Compound
• Binary covalent compounds:
- Contains two nonmetals elements joined together by one or more covalent bonds
- Prefixes indicate the number of atoms of each element that appear in the formula
• Writing names”
1. Name the left most element in the formula first
2. Name the second element making sure the element name end with the suffix ide
3. Add the prefix to each elements name to indicate the number of atoms of each element in the compound
**If the first element has only one atom, do not add a prefix
Prefix Number
Mono- 1
Di- 2
Tri- 3
Tetra- 4
Penta- 5
Hexa- 6
Hepta- 7
Octa- 8
Nona- 9
Deca- 10
Example:
- P4010 tertaphosphrous decaoxidene ne can
Section 4.3- Chemical Equations
Chemical change
• Reactants and Products:
- Involves the conversion of pure substance called reactants into other pure substances called products with different properties from the reactants
- One or more chemical changes that occur at the same time are called chemical reaction
• How it is represented:
- By suing a chemical equation
- May be written in word or chemical symbols
- The symbols for states of matter are solid (s), gas (g) and liquids (l)
Conservation of Mass
• Law:
- Atoms are neither destroyed nor produced in a chemical reaction
- The total mass of the products is always equal to the total mass of the reactants
Writing and Balancing Equations
• Steps:
1. Write a word equation: provides the names of the reactants and products
Example: methane +oxygen water + carbon dioxide
2. Write a Skelton equation (replaces the names of the reactant s and products in a word equation with formulas) THIS IS NOT BALANCED!
Example: CH4 + 02 H20 + CO2
3. Write a balanced equation: shows the identities of each pure substance involved in the reaction. Uses lowest number coefficients. What you start with you must end with!!!
Example: CH4 +2O2 2H20 + CO2
Chapter 5: Compounds are classified in different ways
Section 5.1: Acids and Base
Acids and Bases
• pH Scale:
- A number scale for measuring how acidic or basic a solution is.
- Less than 7 acidic
- More than 7 basic
- pH of 7 neutral (neither acidic or basic)
pH values of common substances
• Acids:
- Chemical compounds that produce a solution with a pH of less than 7 when they dissolve in water.
- Taste sour, will burn you skin, they corrode metals, conduct electricity.
• Bases:
- Compounds that produce a solution of pH of more than 7 when dissolve in water.
- Taste bitter, feel slippery, many will burn your skin, no reaction to meals, conduct electricity.
pH Indicators
• pH Indicators Used For:
- Chemicals that change color depending on the pH of the solution they are placed in.
- Blue litmus paper turns red in an acidic solution.
- Red litmus paper turns to blue in a basic solution.
- Phenolphthalein, bromothymol blue, indigo carmine, methyl orange and methyl red are other common ph indicators.
Naming Acids and Bases
• Acids:
- Chemical formulas are usually written with an H on the left side of the formula.
- If no state of matter is given, the name may be given beginning with hydrogen, as in hydrogen chloride.
- If acids is shown as being aqueous as in HCI(aq), a different name may be used that ends in “-ic acid” as in hydrochloric acid.
• Names of Acids:
- Names that begin with hydrogen and end with the suffix “-ate” can be changed by dropping “hydrogen” from the name and changing the suffix to –ic
Example: H2CO3- hydrogen carbonate
• Bases:
- They are usually written with an OH on the right side of the formula.
- Common names of bases include sodium hydroxide and magnesium hydroxide.
Section 5.2: Salts
Acid Base Neutralization
• Neutralization (acid base):
- acid and a base react to form a salt and water
Example: HCI + NaOH NaCI + H2O
Metals Oxides and Non-Metal Oxides:
• Metal Oxides:
- Contains a metal chemically combined with oxygen.
- The solution becomes basic
Example: Na2O(s) + H2O 2NaOH(aq) (a base Sodium hydroxide
• Non-Metals Oxides
- Contains a non-metal chemically combined with oxygen.
- The solution become acidic
Example: CO2(g) + H2O(l) H2CO3(aq) Carbonic acid
Acids, Metals and Carbonates
• Acids and Metals:
- When metals react with acids to produce salt, they usually release hydrogen gas
- The most reactive metal are the alkali metals and the alkaline earth metals.
- The bottom of the columns reacts most vigorously.
• Carbonates:
- React with acids to produce salts.
- Much of the carbon dioxide on the surface of the earth is trapped in rocks, such as limestone, dolomite, and calcite.
- Carbonates help to neutralize acids.
Section 5.3: Organic Compounds
Organic Compounds
• Organic and Inorganic Compounds:
- Organic compounds are any compounds that contain carbon (with a few expectations)
- Carbon in organic compounds forms four bonds.
- To recognize a compound as organic: Look for an indication of the presence of the presence of carbon in its name, chemical formula or diagram.
- Inorganic compounds include compounds that generally don’t contain carbon and also a few exceptions to the organic classification (i.e. carbon dioxide, carbon monoxide, and ionic carbonates).
Hydrocarbons
• A hydrocarbon:
- An organic compound that contains only the elements carbon and hydrogen (simples is methane)
Alcohols
• Alcohol:
- One of a kind organic compound that contains C. H, and O.
- Many types such as methanol, ethanol and isopropyl alcohol.
- A solvent is a liquid that can dissolve other substances.
Chapter 6: Chemicals Reactions
Section 6.1- Types of Chemical Reactions
Chemical Reactions
• Six main types:
- Synthesis
- Decomposition
- Single replacement
- Double replacement
- Neutralization (acid, base)
- Combustion
Synthesis
• Synthesis (combination) reactions:
- Two or more reactants (A and B) combine to produce a singe product (AB). A + B AB
Decomposition
• Decomposition reaction:
- A compound is broken down into smaller compounds or separate elements.
- The reverse of a synthesis reaction.
Example: compound element + element
AB A + B
Single Replacement
• Single Replacement reaction:
- A reactive element (a metal or non-metal) and a compound react to produce another element and another compound react to produce another element and another compound.
- One of the elements in the compound is replace by anther element.
- The element that is replaced could be a metal or a non-metal.
Example: element + compound element + compound
A + BC B + AC where A is a metal OR
A + BC C + BA where A is a non-metal
Double Replacement
• Double Replacement Reaction:
- Usually involves two ionic solutions that react to produce two their ionic compounds.
- One of the compounds forms a precipitate, which is an insoluble solid that forms a solution.
Example: ionic solution + ionic solution ionic solution + ionic solution
AB(aq) + CD(aq) AD(aq) + CB(s)
Neutralization (acid-base)
• Neutralization (acid-base) reaction:
- When an acid and a base are combined, they will neutralize each other.
- An acid and a base react to form a salt and water.
Example: acid + base salt + water
HX + MOH MX + H20 (X= negative ion, M= positive ion)
Combustion
• Combustion reaction:
- The rapid reaction of a compound or element with an oxygen to form an oxide and produce heat.
Example: hydrocarbon + oxygen carbon dioxide + water
Section 6.2- Factors Affecting Chemical Reactions
Rate of Reaction
• Rate of reaction:
- How quickly or slowly reactants turn into products.
- A reaction that takes a long time has a low reaction rate.
- A reaction that occurs quickly has a high reaction rate.
- A rate describes how quickly or slowly a change occurs.
• Factors affected rate of reaction:
- Temperature
- Concentration
- Surface Area
- Catalyst
Temperature
• Increasing + Higher Temperature:
- Causes the particles (atoms or molecules) of the reactants to move more quickly so that they collide with each other more frequently and with more energy.
- The higher the temperature the greater the rate of reaction.
• Decreasing + Lower Temperature:
- If you decrease temperature the particles move more slowly, colliding less frequently and with less energy.
- The rate of reaction decreases.
Concentration:
• Greater Concentration:
- if a greater concentration of reactant atoms and molecules is present, there is a greater chance that collisions will occur among them.
- More collisions mean a higher reaction rate.
- Increasing concentration of the reactants usually results in a higher reaction rate.
- When you blow on a campfire, you are increasing the concentration of oxygen near the flames,
• Lower Concentration:
- There is less chance for collision between particles.
- Decreasing the concentration of the reactants results in a lower reaction rate.
Surface Area
• For the same mass:
- Many small particles have a greater total SA than one large particle.
- The more surface contact between reactants, the higher the rate of reaction.
- The less surface contact, the lower the reaction rate.
Catalyst
• A catalyst:
- Substance that speeds up the rate of a chemical reaction without being used in the reaction itself.
- Reduce the amount of energy required to break and form bonds during chemical reaction.
- A reaction can proceed although less energy is added during the reaction.
• Enzymes
- Catalysts that allow chemical reactions to occur ate relatively low temperatures within the body.
- Large organic molecules, usually proteins, which speed up reaction in living cells.
- Each enzyme in your body is specialized to perform its own function.
Chapter 7: The Atomic Theory
Section 7.1- Atomic Theory, Isotopes and Radioactive Decay
Radioactivity
• Radioactivity:
- The release of high-energy particles and rays of energy from a substance as a result of changes in the nuclei of its atoms.
- Radiation refers to high-energy rays and particles emitted by radioactive sources.
- Includes radio waves, microwaves, infrared rays, visible light and ultraviolent rays
- Light is one form of radiation that is visible to humans.
Isotopes:
• Isotopes:
- Different atoms of a particular element that have the same number of protons but different numbers of neutrons.
- All isotopes of an element have the same atomic number (protons), however, since the number of neutrons differs, the mass number and atomic mass differ from one isotope to the next.
• Mass number:
- An integer (whole #) that represents the sum of an atom’s protons and neutrons.
Mass number = atomic number + number of neutrons
Number of protons = mass number – atomic number
• Representing Isotopes:
- Includes the chemical symbol, atomic number and the mass number.
- The mass number is written as a subscript (above) on the left of the symbol.
- The atomic number is written as a subscript (below) on the left.
Radioactive Decay
• Radioactive Decay:
- The process in which unstable nuclei lose energy by emitting radiation.
- By emitting radiation, atoms of one kind of element can change into atoms of another element.
- Radioisotopes are natural or human-made isotopes that decay into other isotopes, releasing radiation.
- Three types of radiation: alpha, beta and gamma.
Property Alpha Radiation Beta Radiation Gamma Radiation
Symbol 42He or 42a 0-1b or 0-1e 00y
Composition Alpha particles Beta particles High-energy Radiation
Description Helium nuclei Electrons High energy rays
Charge 2+ 1- 0
Relative Penetrating Blocked by paper Blocked by metal foil Partly/completely blocked
Power Or concrete By lead
Alpha Radiation:
• Alpha particles:
- Positively charged atomic particles that are much more massive that either beat and gamma radiation.
- Same combination of particles as the nucleus of a helium atom.
- Alpha particle has a mass number of 4 and an atomic number of 2, two protons and two neutrons.
- Has an electric charge of 2+.
- Relatively slow moving compared with other types of radiation.
- Not very penetrating- a single sheet of paper stops alp ha particles.
• Alpha decay:
- The emission of an alpha particle from a nucleus.
Beta Radiation:
• Beta particle:
- An electron that has a mass number of 0.
- Has an electric charge of 1-.
- Beat particles are lightweight and fast moving that have a greater penetrating power than alpha particles.
- A thin sheet of aluminum foil can block beta particles.
• Beat Decay:
- A neutron changes into a proton and an electron.
- Proton remains in the nucleus while the electron shoots out from the nucleus with a lot of energy.
- The atomic number increases by one- it has become an atom of the next higher element.
- The mass number does not change.
Gamma Radiation
• Gamma Radiation:
- Consists of rays of high-energy, short-wavelength radiation.
- Have almost no mass and no charge. The release of gamma radiation does not change the atomic number or the mass number of a nucleus.
- Highest energy form of electromagnetic radiation.
• Gamma Decay:
- Results from a redistribution of energy within the nucleus.
- A gamma ray is given off as the isotope changes from high-energy to a lower energy state.
Section 7.2- Half-Life
Carbon Dating
• Radiocarbon dating:
- The process of determining the age of an abject by measuring the amount of carbon-14 remaining in that object.
- Carbon isotopes include carbon-23 and carbon-14.
- When an organism is alive the ratio of carbom-14 atoms to carbon-12 atoms in the organism remains nearly constant.
• The Rate of Radioactive Decay:
- Half life- is a constant for any radioactive isotope and is equal to the time required for a half the nuclei in a sample to decay.
• Using a Decay Curve:
- A decay curve is a curved line on a graph that shows the rate at which radioisotopes decay.
Common Isotope Pairs
• Parent and Daughter Isotope
- The isotope that undergoes radioactive decay is called the parent isotope.
- The stable products of radioactive decay are called the daughter isotope.
- The production of a daughter isotope can be a direct reaction or the result of a series of decays.
Parent Daughter Half Life of Parent Effective Dating Range
Carbon-14 Nitrogen-14 5730 Up to 50 000
Uranium-235 Lead-207 710 million > 10 million
Potassium-40 Argon-40 1.3 billion 10 000 to 3 billion
Uranium-238 Lead-206 4.5 billion > 10 million
Theorium-235 Lead-208 14 billion > 10 million
Rubidium-87 Strontium-87 47 billion > 10 million
The Potassium-40 Clock
• How it Works:
- It uses radioisotopes, specifically potassium-40 and argon-40, to determine Earths age.
- When rock is produced from lava, all the gases (including potassium-40) in the molten rock are driven out, this process sets the potassium radioisotope clock to zero.
Section 7.3- Nuclear Reactions
Nuclear Fission
• Nuclear Fission:
- The splitting of a big nucleus into two smaller nuclei, subatomic particles and energy.
- Heavy nuclei are unstable due to repulsive forces between the many protons.
- To increase stability, atoms with heavy nuclei may split into atoms with lighter nuclei.
- Fission is accompanied by a very large release of energy.
- 4He2 +14N7 17O8 + 1H1
• Nuclear Fission of Uranium-235:
- When a nucleus of uranium-235 is stuck by or bombarded with a neutron, the nucleus absorbs the neutron.
- Result, the mass number of the nucleus increases by one.
- Because the number of protons had not changed, this is still an atom of uranium (just different isotope.)
- When a uranium nucleus undergoes fission, they release neutrons, which trigger more fission reactions.
Nuclear Fusion
• Nuclear Fusion:
- The processes in which two low mass nuclei join together to make a more massive nucleus.
- It occurs at the core of the Sun and other stars, where there is a lot of pressure and high enough temperature to force isotopes of hydrogen to collide with great force.
- 2H1 + 3H1 4H2 + 1n0 + energy
- We don not currently have the technology to extract energy from fusion reactions.
Comparing Nuclear Fission and Fusion:
Nuclear Fission Nuclear Fusion
Beginning Heavy unstable nuclei split apart in two smaller nuclei. Two lightweight nuclei join together to form a heavier nucleus.
Releases Unstable nuclei release a huge amount of energy when they split. Lightweight nuclei release a huge amount of energy when they join.
Energy Heavy nuclei- don’t release energy Lightweight nuclei- will not release energy
Products Produce daughter products that are radioactive. No not produce products that are radioactive.
Technologies Many countries generate some electrical power through fission reactions. No commercial fusion reactors are in use or under construction.
Research Try to produce environmentally friendly nuclear power generation Try to produce a fusion nuclear reactor.
Used Used in modern nuclear weapons Used in modern nuclear weapons to generate most of the energy released in the blast.
Nuclear Equation:
• A nuclear Equation:
- A set of symbols that indicates changes in the nuclei of atoms during a nuclear reaction.
• Rules:
1. The sum of the mass numbers on each side of the equation stays the same.
2. The sum of the charges (represented by atomic number) on each side of the equation stays the same.
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