Unit C: Environmental Chemistry

 Learning Targets

Pre-assessment: What do you know?


Figure C.P.1 – Dissolved chemicals in water affect aquatic organisms.

Figure C.P.2 – Acid rain kills trees.


Figure C.P.3 – All living things require nutrients.
Many different chemicals are found in the environment. Some of these chemicals are helpful to living things. All organisms, including humans, need to take in many different types of nutrients to be healthy and stay alive.

Other substances in the environment can cause great harm to living things. The spread of harmful substances in the environment are usually a result of human actions. Harmful chemicals can affect organisms and ecosystems far away from the pollution source.

In order to maintain healthy ecosystems, governments and scientists measure the amounts of different chemicals in the environment. They monitor these measurements over time, to determine if changes occur.

What types of chemicals are helpful for living things? What types of chemicals are harmful to living things? How do scientists describe measurements of environmental chemicals?

To learn more about how we can keep ecosystems safe for living things, we must first understand the effects of different chemicals in the environment.


Figure C.P.4 – Scientists measure and monitor the amounts of chemicals in the environment.

Figure C.P.5 – Farming chemicals can lead to algae growth in waterways.

Pre-assessment Questions & Hints

Step 1: The Questions


This short pre-assessment is to find out what you might already know about the topic of environmental chemistry. Below are four questions. Think about them! If you need a hint, click on the question.

Optional: If you would like a place to write your answers, download this document. If you prefer to use a Google Drive or PDF version of this pre-assessment, click here.

Step 2: The Answers

 Click each of the suggested answers below – how do they compare to your thoughts and answers?

Many nutrients in the environment are necessary for living things to stay alive. For example, all living things need oxygen and carbohydrates for cellular respiration. Organisms also need protein for cell structures and fats to store energy. Plants need carbon dioxide and water for photosynthesis.
The pH scale, from 0 to 14, describes how acidic or basic a substance is. On the pH scale, acidic substances measure less than 7, neutral substances measure exactly 7, and basic substances measure greater than 7. Vinegar and lemon juice are examples of acids. Baking soda and bleach are examples of bases.
Several chemicals are harmful to organisms and ecosystems. Some examples include:
  • Pesticides such as DDT can build up in the higher levels of food chains. For example, birds of prey containing high concentrations of DDT produce weak-shelled eggs which crack before baby birds can fully develop.
  • Sulfur oxides and nitrogen oxides from burning fossil fuels contribute to acid rain. High acid levels kill plants and aquatic organisms.
  • Heavy metals such as mercury and lead can enter the environment from various industries. Heavy metals can build up in higher levels of food chains, and cause effects like damage to brain cells.
Harmful chemicals can travel in the environment in ways such as:
  • Gases released from smokestacks and cars can travel far away from their source by wind.
  • Pollutants, such as extra fertilizer, can be washed off land by rain into lakes and rivers.
  • Pollutants can leach through soil into groundwater.

Step 3: Check In With Your Teacher

The start of a new unit is a great time to touch base with your teacher! Here are just a few reasons to consider contacting your teacher:

  1. Perhaps you found this pre-assessment quiz very easy because you have studied this material before, such as at another school. If so, it's important to tell your teacher.

  2. It's very good for your teacher to know you are starting a new unit; it will give them a good idea of your progress. It doesn't have to be a long message, just a "I'm starting Unit A; just thought you might want to know!"

  3. Your teacher may have special tips and suggestions for the unit you are starting.

  4. Just to say hi – your teacher always enjoys hearing from you!

To contact your teacher, post in the Course Questions Forum, send your teacher an email, or call on the phone if you like. Whatever way you choose, it's always a good idea to get in touch with your teacher – make sure you do it frequently.