1. Unit C: Environmental Chemistry
Section 1: The environment is made up of chemicals that can support or harm living things.
First Nations people made use of chemicals in their environment for food and medicine. They recognized the benefits of drinking willow bark tea.
In Europe as well, willow bark had been used since at least 400 B.C. At that time, Hippocrates, now known as the Father of Medicine, had recommended it to treat pain and fever. The active ingredient in willow bark was identified in the 1800s as salicylic acid, Aspirin. The synthetic name of this chemical is called acetylsalicylic acid.

2. 1.1 Chemicals in the Environment
Trees, mountains, the air we breathe, our own bodies – everything that makes up the environment is made of chemicals. All living things are made of chemicals and depend on chemicals to survive.
Not all chemicals that form the environment support living things. For example, forest fire and volcanoes both release large quantities of chemicals such as carbon dioxide, sulfur dioxide, and ash. Even though these substances are produced naturally, they can be harmful to living things.

3. The Nitrogen Cycle
Nitrogen is important for living things. 78% of air is made up of nitrogen gas, “free” nitrogen.
- Free nitrogen cannot be used by plants, it has to be “fixed” in compounds with other elements. This process is called nitrogen fixation.
- How do you “fix” nitrogen?
Certain bacteria do most of the nitrogen fixation in the soil. As well, lightning also converts nitrogen in the air to nitrogen compounds that plants can use. When the animals eat plants, they take in the nitrogen to create proteins. Decomposers break down these large nitrogen-containing molecules in dead organisms and animal waste into simpler nitrogen compounds in the soil. Sometimes the bacteria further break down this simple nitrogen and release it into the air as “free” nitrogen.

4. The amount of nitrogen in the soil varies because:
- too many bacteria converting “fixed” nitrogen to “free” nitrogen.
- water could carry the nitrogen down into the soil so deep that plants do have access to it.
- farmers remove all plants from an area.
- If soil lacks nitrogen, farmer plant nitrogen-fixing plants such as clover and alfalfa or add fertilizers to increase the amount of nitrogen

6. Processes and Activities that Affect Environmental Chemicals:
1. Nitrogen Cycle
2. Cellular Respiration:
Food + Oxygen Carbon dioxide + Water
3. Pollution: Vehicle exhaust adds chemicals to the air. Oxygen is needed to run an engine, but an engine gives off carbon dioxide, carbon monoxide, nitrogen oxides, and water vapor into the air.

7. Fertilizer: a substance that enriches soil so that plants will grow better
The three numbers on the bag represent the amount of:
1. nitrogen
2. phosphorus
3. potassium

8. OR, we have natural fertilizer!

9. Too much fertilizer can damage crops, organisms, and may enter ponds, streams, lakes, and rivers hurting ecosystems.
5. Pesticides, herbicides, fungicides and insecticides: These chemicals not only hurt the organisms they are intended to hurt but other and their surrounding environment.