Science 9: Unit 3 - Environmental Chemistry

Science 9: Unit 3 - Environmental Chemistry Topic 1.1 - Chemicals in the Environment   The three cycles we learned about in this unit are the Water Cycle, Carbon Cycle, and the Nitrogen Cycle.   The Water Cycle: Water starts as a liquid in surface water or as water in leaves. Then the water transpires from the leaves and vaporizes from the surface water, becoming water vapour in the atmosphere. Then it condenses into clouds, and water keeps filling up in clouds. Once the clouds are over-filled, water falls in liquid form, called precipitation. The water then drains into surface and groundwater, ready to be evaporated again.

The Carbon Cycle: Carbon is given off by factories and dead and alive organisms, usually in the form of carbon dioxide. Then the carbon dioxide is absorbed by plants or goes into the soil and slowly forms coal. Then the plant dies and creates more carbon dioxide, ready to be absorbed again.

The Nitrogen Cycle: Nitrogen gets into the soil through decay and animal waste and then gets rid of bacteria in the roots of plants. It mixes with ammonium and oxygen in the soil. Then it separates and goes back into the atmosphere. To make nitrogen useful, it must be combined with something else, called "Nitrogen Fixation". Nitrogen then goes back into the soil, ready to be used again.

Nitrogen Fixation: Changing free nitrogen so that the atoms can combine with other elements that organisms can use. This happens with lightning.  

Science 9: Unit 3 - Environmental Chemistry Topic 1.2 - Human Activities and Their Impact   AGRICULTURAL: Fertilizer: A substance that enriches the soil, allowing plants to grow better. Made up of nitrogen, phosphorus and potassium Positives: - Encourages growth Negatives: - Too much can damage soil - Gets into water and damages ecosystems   Pesticides: A chemical used to kill pests(pests harm people, crops, or structures).  Insecticide = Bugs Herbicides = plants and weeds Fungicide = Fungus Positives: - Kills pests Negatives: - Pests can build immunities to overused pesticides - Cause cancer, poisonous to many other organisms   HUMAN WASTE DISPOSAL Solid Waste: Garbage taken from anywhere humans are. Some are recycled while most are sent to landfills. In landfills, the waste is burned and then buried into the ground. Sanitary landfills have a clay lining that tops damaging chemicals getting into the soil Positives: - Get rid of our waste Negatives:  - Take up space - Dangerous chemicals can leak into the soil - Incinerators cause air pollution

Waste Water: Water that is taken from human places. It can be dangerous if not cleaned. In a rural area, it is taken to a septic tank. In an urban area, it is taken to a sewage treatment plant. Storm sewers take excess rainwater that rolls down the streets can carry dangerous chemicals. Effluent is treated wastewater. Stages of Cleaning: Physical - Large material removed Biological - Bacteria removes smaller material Chemical - Chemical cleaners are added Positives: - Clean water is safe! Negatives: - Uncleaned water can pollute the environment, magnifies down the food chain

Fuel Combustion and Industrial Processes: Involve gases reacting to aid us mechanically. Combustion reactions are used to get lots of energy Eg. Gasoline and factories Positives: - Transportation, heating and using power are easier Negatives: - Lots of CO2 is released - Causes air pollution   - Acid rain   - Global warming

Science 9: Unit 3 - Environmental Chemistry Topic 1.3 - Common Substances Essential to Living Things   Organic Substances: Contain the element carbon, there are more of these. CO2 and CO aren't organic Inorganic Substances: Do not contain the element carbon    Nutrients are things that we need to live! Macronutrients: Are needed in large amounts(made of oxygen, carbon, nitrogen and hydrogen) - Carbohydrates: Provide energy(C, H, O) - Proteins: Helps us grow and repair(C, H, O, N) - Lipids: Store energy(C, H, O) - Nucleic Acids: Found in nucleus Micronutrients: Are needed in small amounts - Iron - Copper - Many other metals   Nitrogen: Growth and repair in humans and plants Phosphorus: Growth, bones and photosynthesis Potassium: Early growth in both, muscles in humans Magnesium: Photosynthesis, bone composition Calcium: Muscles and bones, cell wall Sulfur: Proteins, fruit production

Science 9: Unit 3 - Environmental Chemistry Topic 1.4 - The Intake of Substances   Intake In Plants: Diffusion: Molecules move from high concentration to low concentration in the plant roots Osmosis: Molecules moving through water through a semi-permeable membrane(high concentration to low concentration) Active Transport: Movement from low concentration to high concentration using energy   Intake in Animals: Ingestion: Taking food into the body Hydrolysis: Using water to break down food(saliva)   Animals can access nutrients on a substrate: Substrate: The material a substance lives or moves on Examples: Algae growing on water(water gives algae nutrients) - Mold growing on bread

Science 9: Unit 3 - Environmental Chemistry Topic 2.1 - Acids and Bases   Acidity: The measure of how many hydrogen ions are in a substance(more ions = more acidic) pH: On a scale from 0 -14. 0 = acid, 7 = neutral, 14 = base. Use a base-10 system   Acids: Have a pH lower than 7 Eg. Tomatoes, vinegar, battery acid - Taste sour - Conducts electricity   Bases: Have a pH higher than 7 Eg. Ammonia, baking soda, shampoo - Tastes bitter - Conducts electricity - Corrodes   Neutralization: Acids and bases will react with each other to form a salt, water and gas Eg. Antacid, vinegar   Acid Indicators: Express the pH of a substance - Blue Litmus Paper: Turns red when there's an acid - Red Litmus Paper: Turns blue when there's a base - Bromothymol Blue: Turns yellow when there's an acid - Phenolphthalein: Turns red when there's a base - Universal Indicator: Color = acidity

Effects on the Environment:   Acid Rain: Rain with a pH lower than 5.3. Caused by factory emissions. - Stops fish eggs - Slow plant growth   Acid Spring Shock: Acidification of runoff - Stops fish spawning  

Science 9: Unit 3 - Environmental Chemistry Topic 3.1 - Monitoring Water Quality   Water quality is determined by what it's used for. - Human Drinking - Recreation - Livestock Drinking - Irrigation - Aquatic Life Protection   Biological Indicators: Organisms that live in water and allow us to determine the water quality(some organisms can survive in tougher conditions) Lots of pollution = Dragonflies, beetles Little pollution = Mayflies, stoneflies   Inorganic Chemical Factors: - Dissolved Oxygen: Amount of oxygen in water, more is better   - Temperature   - Turbulence   - Photosynthesis   - # of Organisms - Acidity: Level of pH - Heavy Metals: Metals denser than 5g/cm3 are dangerous - Plant Nutrients: Amount of phosphorus and nitrogen(excess can cause sewage outfalls and fertilizer run-off)   - Nitrates are bad, result from excess fertilizer, etc. Can cause health problems to both humans and aquatic animal diversity   - Excess phosphorus comes from too many algae. It also lowers oxygen levels and sunlight for other plants - Toxicity: Can cause health problems to organisms   River Diagrams:   Headwaters: Where it starts Floodplain: Where it overflows too Mouth: Where it ends  

Science 9: Unit 3 - Environmental Chemistry Topic 3.2 - Measuring Chemicals in the Environment   LD50: A certain amount of a substance that has a 50% chance of killing you(depends on mass) Eg, A 2000g rat eats 1500g of LD50, it dies Examples: - Caffeine - Table salt   Parts Per Million: The concentration of chemicals. A ppm(part per million) is a millionth of a substance.  - Part per Billion  - Part per Trillion   Formula: Mass of solute(g, kg)/ total volume of solution(mL, L) x 1,000,000 for ppm(1 B for ppb and 1 T for ppt)   *If poison does damage at ppt, it is very powerful.   Example Problem: Pool has 2,500,000 L of water. 6.75 g of salt is dissolved, what is its ppm? 1. Make sure the units are equivalent(l = kg, mL = g, etc.) They aren't, so convert L to mL: 2,500,000 x 1000 = 2,500,000,000 mL 2. Divide! 6.75 g/ 2,500,000,000 mL = 0.0000000027 3. Multiply! 0.000000027 x 1,000,000 = 0.0027 ppm   Answer: 0.0027 ppm!  

Science 9: Unit 3 - Environmental Chemistry Topic 3.3 - Monitoring Air and Atmosphere Quality   Air Pollutants:   Sulfur Dioxide: Comes from oil and gas burning, forms acid and causes lung problems Nitrogen Oxides: Comes from electric utilities, forms acid rain Carbon Monoxide: Comes from burning carbon, kills organisms Ground Level Ozone: Comes from overheated ozone layer, causes lung problems Chlorofluorocarbons: Comes from fridges and aerosal cans, breaks down ozone layer   Atmosphere Quality:   Important Greenhouse Gases: - Water vapour (H2O) - Carbon dioxide (CO2) - Nitrogen oxides (N2O) - Methane (CH4)   Greenhouse Effect: A naturally occurring event, resulting in greenhouse gases being trapped, making our planet warm and habitable Enhanced Greenhouse Effect: Higher global temperatures caused by an excess of greenhouse gases Global Warming: Heat from the sun is trapped by greenhouse gases, caused by human activities. Results in unpredictable climate and ice caps melting. Political opinions on it are that we must charge people on their carbon usage to get them to reduce it.   Technologies to Reduce Impact:   - Scrubbers - Catalytic converters in cars - Planting vegetation  

Science 9: Unit 3 - Environmental Chemistry Topic 4.1 - Transportation of Chemicals Throughout the Environment   Stages to Chemical Movement:   Point Source: Chemical comes from one specific spot Non-point Source: Chemical comes from a large area   Release: Where the chemicals originate Eg. Littering Dispersion: Chemicals are spreading out Eg. Wind moving chemicals Deposition: Where the chemicals end up Eg. Water, Air, or Soil   Transportation of Chemicals in the Air: Chemicals can get anywhere if they can move through the air Factors: - Wind speed - Wind direction - Mass of chemical - Weather(rain or snow)   Transportation of Chemicals in Water: Chemicals can move long distances in surface water. Chemicals can increase in concentration in groundwater. Factors: - Movement of water - Temperature of water - The shape of the waterway(straighter = faster) - Chemical mass and composition - Amount of pores   Run-off: Excess water that flows over land surfaces, picking up chemicals as it goes   Transportation of Chemicals in Soil: Chemicals can increase in concentration as they move downwards Factors: - Amount of pores - Composition of soil - Chemical composition   Biomagnification: The increase in the concentration of a pollutant through the movement of the food chain

Science 9: Unit 3 - Environmental Chemistry Topic 4.2 - Reducing the Harmful Chemicals in the Environment   Dilution: Mixing the chemical with lots of air or water to reduce the concentration Biodegradation: Living things that actively break down waste Eg. Composting - Temperature - Soil Moisture - pH levels (6.5 - 8) - Oxygen Levels - Nutrient Availability   Four R's: Reuse, Reduce Recycle, Recover   Phytoremediation: Plants that absorb harmful chemicals Photolysis: Breaking down compounds using sunlight   Properly cleaning and taking care of chemicals also helps the environment!  

Science 9: Unit 3 - Environmental Chemistry Topic 4.3 - Viewpoints of Human Activities   Ethical: Is it right to destroy the environment for our needs? Political: Who has to clean up messes? Will this help the country? Economic: Is it financially viable to continue supporting the environment? Environmental: How have our actions changed the environment? Is it all negative?