Mechanical and Chemical Weathering Quiz

Samples of limestone, granite, quartz, and stalactite are exposed to acidic groundwater. All other conditions being equal, which rock would weather most quickly?

• the limestone, because the acidic groundwater would dissolve the rock's calcite

• the granite, because the acidic groundwater would oxidize the rock's iron

• the quartz, because it would absorb the water, increasing the rock's density and placing added pressure on its molecules

• the stalactite, because the water would loosen the bonds that hold its molecules together

While exploring an ancient lava field, a geologist discovers a piece of granite that has a coating of soft, crumbling rust. What is the most likely explanation for this rust?

• Exposure to air has caused the iron-bearing minerals in the granite to oxidize.

• At some point in the past, a river flowed over the field, depositing the rust on top of the granite.

• Exposure to acid precipitation has worn away the granite's exterior, revealing its soft interior.

• Snails and fungi living in the lava field have secreted chemicals that reacted with the granite to form rust.

How is chemical weathering different from mechanical weathering?

• Pollutants are formed during chemical weathering.

• New substances are formed during chemical weathering.

• Living things drive the process of chemical weathering.

• Rock is broken down into smaller pieces during chemical weathering.

Why is wind an agent of mechanical weathering?

• Wind carries sediment that causes abrasion of exposed rock.

• Wind carries oxygen molecules that react with iron in exposed rock.

• Wind carries water vapor that dissolves minerals in exposed rock.

• all of the above

What role does temperature play in the process of mechanical weathering?

• Temperature changes cause rocks to expand and contract, leading to fractures.

• Temperature has no effect on mechanical weathering.

• Higher temperatures increase the rate of chemical reactions that weather rocks.

• Temperature only affects the moisture content in the air, not the rocks.

Which type of rock is most susceptible to chemical weathering by acid rain?

• Granite, due to its high quartz content.

• Limestone, because it contains calcite that reacts with acids.

• Basalt, as it is formed from volcanic activity.

• Sandstone, since it is composed of compacted sand grains.

Soil is made up of 4 main ingredients. Choose the correct list of ingredients.

• Humus, clay, water & salts

• Tiny pieces of rock, air, water & humus

• Tiny pieces of rock, humus, air & loam

Which of the following is a good way to slow down erosion on a hill?

• Cut down the tallest trees on the hill

• Dig a hole on the hill

• Plant tall grass on the hill

• Build a fence on the top of the hill

As precipitation rates increase, the rate of chemical weathering…

• Increases

• Decreases

• Remains the same

As precipitation rates increase, the rate of physical weathering…

• Increases

• Decreases

• Remains the same