Compare chemical and mechanical weathering.

The command word in this question is compare. This means you must describe the similarities and/or differences between things, not just write about one.

A question like this is typically worth two marks. You will get one mark for two separate statements on the same feature e.g.

• Chemical weathering is caused by chemical reactions, whereas mechanical weathering involves rocks being disintegrated (1).
• Both weathering processes involve the rock breakdown in situ (1).
• Mechanical weathering is usually associated with temperature extremes, whereas chemical weathering often involves acid rainwater (1).
• Chemical weathering and mechanical weathering are two processes that can cause rocks and other materials on the Earth’s surface to break down over time. (1)
• Chemical weathering occurs when chemical reactions cause a rock to break down into smaller particles. In contrast, mechanical weathering occurs when physical forces, such as wind, water, or ice, cause a rock to break apart. (1)
• Chemical weathering occurs when the chemical composition of a rock is altered by exposure to water, oxygen, or other substances. In contrast, mechanical weathering occurs when physical forces act directly on the rock to cause it to break apart. (1)
• Chemical weathering can occur relatively quickly, especially in warm, moist environments where chemical reactions happen quickly. Mechanical weathering, on the other hand, can take much longer to occur, as it depends on the action of physical forces over time. (1)

AO4 – 2 marks