Name: 
 

Weathering and Soil



Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

The difference between mechanical and chemical weathering is ____.
a.
the length of time each takes to break up a rock
b.
that only chemical weathering involves water
c.
the way they affect the makeup of a rock
d.
all of the above
 

 2. 

Decayed organic material turns into a dark colored material called ___________.
a.
litter
c.
humus
b.
clay
d.
soil
 

 3. 

Chemical weathering ____.
a.
is caused by freezing and thawing
b.
breaks apart rocks by physical processes
c.
occurs when chemical reactions dissolve or change the minerals in rocks
d.
none of above
 

 4. 

The B horizon is ____.
a.
rockier than the C horizon
c.
lighter in color than the A horizon
b.
richer in humus than the A horizon
d.
thinner than the C horizon
 

 5. 

The rate of weathering depends upon the area's ____.
a.
oxygen
c.
water
b.
climate
d.
soil
 

 6. 

All of the following cause mechanical weathering EXCEPT ____.
a.
ice
c.
burrowing animals
b.
tree roots
d.
carbonic acid
 

 7. 

Each layer of a soil profile is called a __________.
a.
horizon
c.
humus
b.
horizontal
d.
litter
 

 8. 

mc008-1.jpg
Which of these layers would contain the most humus?
a.
A
c.
C
b.
B
d.
all have the same amount
 

 9. 

Mechanical weathering ____.
a.
breaks apart rocks by physical processes
b.
occurs when chemical reactions dissolve or change the minerals in rocks
c.
occurs when iron is exposed to oxygen and water
d.
none of the above
 

 10. 

Soil is a mixture of weathered rock, mineral fragments, water, air and ____.
a.
sand
c.
moss
b.
decayed organic matter
d.
clay
 

 11. 

____ regions are especially vulnerable to erosion because their soils are useful to farmers for only a few years before their nutrients are gone.
a.
Desert
c.
Mountain
b.
Tropical
d.
Prairie
 

 12. 

Chemical weathering is more rapid in a ____ climate.
a.
warm, dry
c.
cold, dry
b.
warm, wet
d.
cold, wet
 

 13. 

The ____ horizon has smaller rock and mineral particles than the other layers.
a.
A
c.
C
b.
B
d.
D
 

 14. 

Soil is a mixture of __________.
a.
weathered rock and water
c.
mineral fragments
b.
decayed organic matter and oxygen
d.
all of these
 

 15. 

Why is ice wedging most obvious in the mountains?
a.
because the altitude directly contributes to how the water freezes in the cracks of rocks
c.
because the pressure in the mountains allows for the repeated freezing and thawing of water caught in cracks of rocks
b.
because gravity pulls on the water in the cracks more if its found higher in the mountains
d.
because the temperature changes in the mountains allow for the repeated freezing and thawing of water caught in cracks of rocks
 

 16. 

Mechanical weathering is more rapid in a ____ climate.
a.
dry
c.
cold
b.
hot
d.
humid
 

 17. 

Soils in ____ contain little organic material and are thin.
a.
tropical areas
c.
prairies
b.
deserts
d.
temperate forests
 

 18. 

Below the C horizon is ____.
a.
topsoil
c.
clay
b.
rock
d.
humus
 

 19. 

When water mixes with carbon dioxide in the air, it forms __________.
a.
sulfuric acid
c.
carbonic acid
b.
hydrochloric acid
d.
ozone
 

 20. 

The rock and mineral fragments in soil come from rock that has been ____.
a.
blasted
c.
weathered
b.
carved
d.
chemically treated
 

 21. 

Minerals found in the B horizon were dissolved in water and carried there by a process called ____.
a.
oxidation
c.
weathering
b.
leaching
d.
littering
 

 22. 

Surface processes that work to break down rock are called__________.
a.
erosion
c.
ice wedging
b.
weathering
d.
oxidation
 

 23. 

Plants cannot grow without ____.
a.
rocks
c.
moss
b.
soil
d.
pesticides
 

 24. 

Oxidation occurs when materials containing ____ are exposed to oxygen and water.
a.
iron
c.
kaolinite
b.
carbonic acid
d.
all of the above
 

 25. 

When water mixes with carbon dioxide gas in the air or soil, ____ forms.
a.
carbonic acid
c.
calcite
b.
lactic acid
d.
oxygen
 

 26. 

The organic matter in humus is made of ____.
a.
dead worms
c.
roots
b.
plant stems
d.
all of the above
 

 27. 

How is surface area related to chemical weathering?
a.
Decreased surface area allows for more interactions of rocks with water and oxygen.
c.
Increased surface area allows for more interactions of rocks with water and oxygen.
b.
Increased surface area allows for more interactions of rocks with plants and animals.
d.
Decreased surface area allows for more ice wedging.
 

 28. 

Climate affects soil types; for instance, prairie soils have __________.
a.
thinner A and B horizons due to leaching, which is promoted by rainfall
c.
granitic C horizons because little or no grass grows there
b.
thin, lightly colored A horizons because of the lack of vegetation
d.
thick, dark, A horizons because of all the grasses that contribute organic materials
 

 29. 

Because desert soils contain little organic material, their soil profiles have ____ horizons.
a.
thick
c.
thin
b.
no
d.
b or c
 

 30. 

____ is a factor that affects soil development.
a.
Time
c.
Type of rock
b.
Slope
d.
all of the above
 

 31. 

The layer of soil that contains the most organic material is called the ____ horizon.
a.
A
c.
C
b.
B
d.
D
 

 32. 

A soil's composition is dependent on weathering because __________.
a.
it makes the soil more fertile
c.
it keeps the soil moist
b.
it contributes sediment to the soil
d.
it moves the topsoil to other areas where it is more needed
 

 33. 

In areas where freezing and thawing occur frequently, rocks weather rapidly because of the ____ of freezing water.
a.
evaporation
c.
leaching
b.
expansion
d.
oxidation
 

 34. 

Plants don't grow as well when ____ has been lost.
a.
clay
c.
parent rock
b.
topsoil
d.
slope
 

 35. 

mc035-1.jpg     
In which horizon of a soil profile does leaching normally occur?
a.
A
c.
C
b.
B
d.
neither of these
 

 36. 

In bottomlands where water is plentiful, soil is often ____.
a.
thin
c.
thick
b.
rocky
d.
light
 

 37. 

     
How do chemical and mechanical weathering differ?
a.
Mechanical weathering occurs when rocks are broken by physical processes, and chemical weathering happens when chemical reactions dissolve minerals.
c.
Chemical weathering can occur with the help of water reacting with carbon dioxide, and water has nothing to do with mechanical weathering.
b.
Mechanical and chemical weathering can happen with the help of animals.
d.
Plant roots can help mechanical weathering occur, but have no impact on soil when it comes to chemical weathering.
 

 38. 

Ice wedging is brought about by ____.
a.
carbonic acid freezing on rocks
c.
water freezing and thawing
b.
water and oxygen reacting
d.
rocks colliding with each other
 

 39. 

How does climate affect chemical and mechanical weathering?
a.
Mechanical weathering occurs more rapidly in warm, wet climates, and chemical weathering occurs more in cold climates.
c.
Chemical weathering occurs more rapidly in dry climates and mechanical weathering occurs more in windy climates.
b.
Chemical weathering occurs more rapidly in warm, wet climates, and mechanical weathering occurs more in cold climates.
d.
Chemical and mechanical weathering occur more rapidly in warm, wet climates.
 

 40. 

Litter often covers the ____ horizon.
a.
A
c.
C
b.
B
d.
all of the above
 



 
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