Ocean Acidification: pH and the Ocean's Balance — Quiz

Multiple-Choice Questions

1. On the pH scale, what number represents "neutral" (neither acid nor base)?
A) 0
B) 7
C) 10
D) 14

2. What gas is described as an "acid gas" that causes the ocean to become more acidic?
A) Oxygen
B) Nitrogen
C) Carbon dioxide
D) Hydrogen

3. According to the resource, what is a common property of an acid?
A) Bitter and slippery
B) Sour and can react with or degrade metals
C) Always colorless
D) Dissolves fats and oils

4. What was the ocean's pH about one hundred years ago, and what is it today?
A) 7.4 then 7.0
B) 8.1 then 8.0
C) 9.0 then 8.5
D) 6.5 then 6.0

5. Which of these household items has the approximate pH closest to a base (alkaline) rather than an acid?
A) Lemon
B) Vinegar
C) Baking soda
D) Coca-cola

6. About what fraction of carbon dioxide emitted into the atmosphere from burning fossil fuels ends up in the ocean?
A) One tenth
B) One quarter
C) One half
D) Nearly all of it

7. In humans, a decrease of how much in blood pH can cause acidosis (illness)?
A) 0.01
B) 0.05
C) 0.5
D) 1.0

8. Which human activity is NOT listed in the resource as a source of carbon dioxide emissions?
A) Driving cars, boats, planes, or trains
B) Using electricity in the home
C) Deforestation (removing trees)
D) Recycling paper products

Short-Answer Questions

9. Explain why a small change in the ocean's pH (such as 0.1 units) can actually represent a much larger shift in ocean chemistry. Use the comparison to the human body in your answer.

10. Describe the causal chain explained in the resource that connects burning fossil fuels to changes in marine organism health.

11. Name two solutions individuals or communities can take to help reduce the amount of carbon dioxide that ends up in the ocean.

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Answer Key

1. B) 7
2. C) Carbon dioxide
3. B) Sour and can react with or degrade metals
4. B) 8.1 then 8.0
5. C) Baking soda
6. B) One quarter
7. B) 0.05
8. D) Recycling paper products

9. Sample answer: Even though 0.1 pH units seems small, it represents an exponentially larger shift in chemical balance (a "simplifying model"). This is similar to how in humans, just a 0.05 decrease in blood pH (acidosis) can cause illness such as headaches, confusion, and tiredness — showing that small numerical shifts in pH can have big effects on living things.

10. Sample answer: Burning fossil fuels emits CO2 → the ocean absorbs the CO2 → CO2 is an "acid gas" so it causes the ocean to become more acidic → a small decrease in pH (about 0.1 units) can tip the balance from healthy to unhealthy for marine organisms, similar to how it affects the human body.

11. Sample answers (any two): Use public transportation, bike, or walk instead of driving; green a home with energy-efficient appliances, windows, or insulation; turn off lights when leaving a room; unplug "vampire" electronics like chargers and computers when not in use; talk to local government about improving public transportation or bike lanes.