What causes acid rain to form?

• Water mixing with oxygen in the air

• Sulfur dioxide from burning fossil fuels mixing with water in the air

• Carbon dioxide from plants mixing with sunlight

• Smoke from campfires mixing with clouds

What was one harmful effect of acid rain on rivers and streams?

• It made the water clearer

• It caused fish and algae to disappear

• It made the water warmer

• It helped plants grow faster

Why was the Clark Fork River not badly damaged by acid rain?

• It has a lot of fast-moving water

• It is protected by a natural substance called limestone

• It is located in a very dry area

• It has special fish that can live in acid

What is a buffer solution?

• A solution that changes color when mixed with acid

• A solution that makes things taste sour

• A solution that helps keep the pH from changing much

• A solution that always stays neutral

What is the main job of a buffer in a solution?

• To make the solution colder.

• To change the color of the solution.

• To keep the pH of the solution from changing too much.

• To make the solution taste better.

What natural substance helps the Clark Fork River resist becoming too acidic from acid rain?

• Sand

• Limestone

• Clay

• Wood

What does "buffering capacity" mean for a solution?

• How much liquid the solution can hold.

• How much acid or base the solution can neutralize before its pH changes a lot.

• How quickly the solution can mix with other liquids.

• How much light the solution can absorb.

When using a pH indicator, what is the "end point"?

• The beginning of the experiment.

• The moment the indicator changes color.

• The final amount of liquid in the beaker.

• The temperature at which the experiment ends.