Which process describes the breakdown of rocks by chemical reactions?

The correct answer is chemical weathering, which refers to the process where rocks undergo a transformation due to chemical reactions. During chemical weathering, the minerals within the rocks react with environmental factors such as water, acids, and gases in the atmosphere, leading to changes in their composition and structure. For instance, when carbon dioxide dissolves in rainwater, it forms a weak acid called carbonic acid, which can react with minerals like calcite in limestone, leading to its dissolution.

This process is crucial in shaping landscapes and forming soils, as it significantly alters the minerals present and affects rock stability. The changes can result in weakened rocks and the release of essential nutrients into the soil, supporting plant life.

Other forms of weathering, such as mechanical weathering, focus on the physical breakdown of rocks without altering their chemical composition, while biological weathering involves the contributions of living organisms to the weathering process. Hence, chemical weathering specifically emphasizes the importance of chemical reactions in breaking down rocks.