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Grade 9 · Science · Unit 6 of 10

Chemistry & the Environment

pH, pollutants and water quality

What your child practises

The pH scale, acid rain and neutralization, nutrients and fertilizer runoff, indicator species, how substances such as mercury build up in food chains, and why the amount of a substance matters for safety.

Nunavut Curriculum approved guide: Nunavut adaptation of Alberta Science 7–9 (2003), Unit C: Environmental Chemistry · acids and bases, nutrients and pollutants, air and water quality, and how substances build up in living things

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    DDT and mercury are hard for living things to break down. What happens to them in a food chain?

    • They disappear at each step
    • They build up in the bodies of animals higher in the chain
    • They are all passed to the producers
    • They are found only in plants

  2. Question 2

    Fertilizer from fields runs off into a lake and the water turns green with algae. This is caused mainly by too much…

    • oxygen
    • phosphorus and nitrogen
    • ice
    • helium

  3. Question 3

    A solution has a pH of 10. What is it?

    • neutral
    • a base
    • an acid
    • a gas

  4. Question 4

    A 4 L water sample contains 36 mg of nitrate. What is the concentration, in mg per litre?

    answer boxmg/L

  5. Question 5

    Which is more acidic, a solution with pH 4 or a solution with pH 5?

    • They are equally acidic
    • pH 5
    • pH 4

  6. Question 6

    Which of these is essential for strong bones and teeth?

    • chlorine gas
    • calcium
    • mercury
    • lead

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