GEOG 1113L Lab 5: Weathering and Soils Exam Questions and
Answers 100% PASS-GSU
1. Which process involves the physical breaking of rocks into smaller fragments
without changing their chemical composition?
A. Oxidation
B. Hydrolysis
C. Mechanical Weathering
D. Carbonation
Answer: C
Rationale: Mechanical weathering, also known as physical weathering, involves breaking
rocks into smaller pieces without altering their chemical identity.
2. How does mechanical weathering affect the rate of chemical weathering?
A. It increases the rate by increasing the total surface area.
B. It decreases the rate by removing surface area.
C. It has no effect on chemical weathering.
D. It stops chemical weathering by cooling the rock.
Answer: A
Rationale: Breaking a rock into smaller pieces increases the total surface area available for
chemical reactions to occur.
3. Which of the following is a primary agent of chemical weathering?
A. Wind
B. Gravity
C. Glacial ice
D. Water
Answer: D
,Rationale: Water is the most important agent of chemical weathering as it transports ions
and participates in reactions like hydrolysis.
4. Frost wedging is most effective in which type of climate?
A. Warm and humid tropical climates
B. Climates with frequent freeze-thaw cycles
C. Arid desert climates with no water
D. Extremely cold climates where water is always frozen
Answer: B
Rationale: Frost wedging requires water to repeatedly freeze (expand) and thaw within
rock fractures.
5. Which mineral is generally most resistant to chemical weathering at the
Earth’s surface?
A. Quartz
B. Olivine
C. Pyroxene
D. Calcium-rich Feldspar
Answer: A
Rationale: Quartz is highly stable at surface conditions because its crystal structure is
strong and it lacks cleavage planes.
6. The process where rock layers peel off like the layers of an onion is called:
A. Oxidation
B. Hydrolysis
C. Dissolution
D. Exfoliation
Answer: D
Rationale: Exfoliation, or unloading, occurs when overlying pressure is removed, causing
the rock to expand and crack in sheets.
, 7. Which chemical weathering process is responsible for the ‘rusting’ of iron-rich
minerals?
A. Oxidation
B. Carbonation
C. Hydration
D. Solution
Answer: A
Rationale: Oxidation occurs when oxygen reacts with minerals, particularly those
containing iron, to form oxides like hematite.
8. What is produced when carbon dioxide dissolves in raindrops?
A. Sulfuric acid
B. Carbonic acid
C. Hydrochloric acid
D. Nitric acid
Answer: B
Rationale: CO2 in the atmosphere reacts with water to form a weak carbonic acid, which is
key to dissolving carbonate rocks.
9. Limestone is particularly susceptible to which type of weathering?
A. Oxidation
B. Exfoliation
C. Frost wedging
D. Dissolution/Carbonation
Answer: D
Rationale: Limestone consists of calcite, which easily dissolves in the presence of weak
carbonic acid.
Answers 100% PASS-GSU
1. Which process involves the physical breaking of rocks into smaller fragments
without changing their chemical composition?
A. Oxidation
B. Hydrolysis
C. Mechanical Weathering
D. Carbonation
Answer: C
Rationale: Mechanical weathering, also known as physical weathering, involves breaking
rocks into smaller pieces without altering their chemical identity.
2. How does mechanical weathering affect the rate of chemical weathering?
A. It increases the rate by increasing the total surface area.
B. It decreases the rate by removing surface area.
C. It has no effect on chemical weathering.
D. It stops chemical weathering by cooling the rock.
Answer: A
Rationale: Breaking a rock into smaller pieces increases the total surface area available for
chemical reactions to occur.
3. Which of the following is a primary agent of chemical weathering?
A. Wind
B. Gravity
C. Glacial ice
D. Water
Answer: D
,Rationale: Water is the most important agent of chemical weathering as it transports ions
and participates in reactions like hydrolysis.
4. Frost wedging is most effective in which type of climate?
A. Warm and humid tropical climates
B. Climates with frequent freeze-thaw cycles
C. Arid desert climates with no water
D. Extremely cold climates where water is always frozen
Answer: B
Rationale: Frost wedging requires water to repeatedly freeze (expand) and thaw within
rock fractures.
5. Which mineral is generally most resistant to chemical weathering at the
Earth’s surface?
A. Quartz
B. Olivine
C. Pyroxene
D. Calcium-rich Feldspar
Answer: A
Rationale: Quartz is highly stable at surface conditions because its crystal structure is
strong and it lacks cleavage planes.
6. The process where rock layers peel off like the layers of an onion is called:
A. Oxidation
B. Hydrolysis
C. Dissolution
D. Exfoliation
Answer: D
Rationale: Exfoliation, or unloading, occurs when overlying pressure is removed, causing
the rock to expand and crack in sheets.
, 7. Which chemical weathering process is responsible for the ‘rusting’ of iron-rich
minerals?
A. Oxidation
B. Carbonation
C. Hydration
D. Solution
Answer: A
Rationale: Oxidation occurs when oxygen reacts with minerals, particularly those
containing iron, to form oxides like hematite.
8. What is produced when carbon dioxide dissolves in raindrops?
A. Sulfuric acid
B. Carbonic acid
C. Hydrochloric acid
D. Nitric acid
Answer: B
Rationale: CO2 in the atmosphere reacts with water to form a weak carbonic acid, which is
key to dissolving carbonate rocks.
9. Limestone is particularly susceptible to which type of weathering?
A. Oxidation
B. Exfoliation
C. Frost wedging
D. Dissolution/Carbonation
Answer: D
Rationale: Limestone consists of calcite, which easily dissolves in the presence of weak
carbonic acid.
