Theory question 103
Rocks and Soil Formation(a) What is rock weathering?
(b) State four factors that affect formation of soil.
(c) Explain briefly four types of chemical weathering.
Show the model answer
Model answer
(a) The breaking down of rocks in place into smaller particles by physical, chemical and biological agents
(b) Parent material; climate (rainfall, temperature); living organisms; topography; time
(c) Any four: hydrolysis – water reacts with minerals (e.g. feldspar) producing clay and soluble salts; hydration – minerals absorb water, swell and crumble; oxidation – iron minerals combine with oxygen, weakening rock (rusting); carbonation – carbonic acid dissolves limestone; solution – soluble minerals dissolve in water; reduction
Explanation
Name each chemical process and say what it does to the rock.