2.5 - Practice Questions



Question 1: Which type of weathering creates a rusting effect on minerals?

Looks Good! Correct: This process changes the oxidation state of mineral components, resulting in rusting in some cases. The process can make the mineral more prone to weathering. For example, an iron (II) bearing mineral can be oxidized to iron (III), which has rusty/red features.

Question 2: Use Figure 2 to decide which type of weathering process will dominate in Antarctica? 

Looks Good! Correct: Physical. Notice that under a cold climate environment, the dominant weathering process is physical.

Question 3: Use Figure 1 and the following links to decide which type of weathering process will dominate in central Africa?

View Annual Average Rainfall Map

View Annual Average Temperature Map

Looks Good! Correct: Chemical. Notice that, under a tropical climate environment, the dominant weathering process is chemical. Under this environment, ample moisture and hot temperatures enhance chemical weathering.

Question 4:  One of the experiments shown previously in this lesson demonstrated the hydrolysis of feldspar. How does physical weathering increase the rate of chemical weathering?

 (view Figure 3)

Looks Good! Physical weathering gradually shatters the rock into small pieces. This gives more surface area exposure to chemical weathering. The key here is surface area.

Question 5:  If calcite, a primary component of limestone rock, is only slightly soluble in water, under what environment would you expect this limestone to be dissolved?

Looks Good! In areas where carbonation occurs (humid and warm environments), the acid formed from carbon dioxide and water, slowly dissolves the limestone.
Figure 9.   Image courtesy of C. Geiss

Question 6:  Is pressure exerted by roots on a rock structure physical or chemical weathering? Why?

Looks Good! Tricky question. The answer is both physical and chemical weathering. Although the pressure of growing roots is physical, chemicals released by roots enhance microbiological activity. The chemical by-products of the microbial activity can gradually consume/disintegrate the rock as well.