Question

1. what causes acid rain?
2. how does local geology affect a water bodys ph?

part 5: measuring ph

1. name three ways scientists can measure ph in the field:

a)
b)
c)

1. why should ph be measured at the same time each day?
2. what is the epas recommended ph range for protecting aquatic life?

from __ to __
part 6: critical thinking

1. a lake has a ph of 9.2. based on the factsheet information:

。 is this water acidic, neutral, or basic? ____
。 what problems might aquatic organisms face? ____
。 what might be causing this high ph? ____

1. compare and contrast how ph affects freshwater vs. saltwater environments:

similarities:

Explanation:

1. Acid rain is caused by emissions of sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) which react with water, oxygen and other chemicals in the atmosphere to form sulfuric and nitric acids.
2. Local geology can affect a water - body's pH because rocks and minerals can release substances that either raise or lower the pH. For example, limestone can neutralize acids and raise pH.
3. Three ways to measure pH in the field are: a) pH paper which changes color based on the pH of the solution; b) Litmus paper (a type of pH - indicating paper); c) Portable pH meters which use electrodes to measure the hydrogen - ion concentration.
4. pH should be measured at the same time each day because biological and chemical processes can cause diurnal variations in pH. For example, photosynthesis by aquatic plants can affect the carbon - dioxide levels and thus the pH.
5. The EPA's recommended pH range for protecting aquatic life is from 6.5 to 8.5.
6. A pH of 9.2 is basic. Aquatic organisms might face problems such as reduced solubility of important nutrients, changes in the availability of heavy metals, and stress on organisms adapted to more neutral or acidic conditions. Possible causes of high pH could include the presence of alkaline rocks in the watershed, agricultural runoff with high - pH substances, or industrial waste with alkaline components.
7. Similarities: In both freshwater and saltwater environments, extreme pH values (either too high or too low) can be harmful to aquatic organisms, disrupt chemical equilibria, and affect the availability of nutrients and oxygen.

Answer:

1. Emissions of sulfur dioxide and nitrogen oxides that react in the atmosphere to form acids.
2. Rocks and minerals in the area can release substances that change the pH.
3. a) pH paper

b) Litmus paper
c) Portable pH meters

1. Due to diurnal variations in biological and chemical processes.
2. From 6.5 to 8.5
3. Basic; Reduced nutrient solubility, heavy - metal availability issues, stress on organisms; Alkaline rocks, agricultural or industrial runoff.
4. Extreme pH values can harm organisms, disrupt chemical equilibria, and affect nutrient and oxygen availability.