Which term refers to the gradual wearing away of rock surfaces by chemical processes?

The term that refers to the gradual wearing away of rock surfaces by chemical processes is indeed chemical weathering. This process involves the alteration of the mineral composition of rocks due to chemical reactions, such as hydrolysis, oxidation, and carbonation. These reactions can weaken the rock, ultimately leading to its breakdown and alteration over time. For example, when carbon dioxide mixes with water, it creates a weak carbonic acid that can dissolve limestone. As a result, you see features like sinkholes or caves develop, which illustrate chemical weathering's impact on landscapes.

On the other hand, physical weathering pertains to the breakdown of rocks and minerals through physical forces without changing their chemical composition, such as freeze-thaw cycles. Biological weathering involves the deterioration of rocks due to living organisms, like roots growing into cracks and breaking the rock apart. Mechanical weathering is similar to physical weathering, focusing on the mechanical processes that fragment the rock, which do not involve chemical changes. Understanding these distinctions enhances comprehension of how various weathering processes sculpt the Earth's surface over time.