1a. With equations, explain (1) Oxidation and (il) Dehvaration
5. How does (1) rock type (ii) slope (iii) climate influence weathering?
c. Explair how (i) geological factor and (ii) over grazing cause erosion
1a. Oxidation: Oxidation refers to a chemical reaction in which an element or compound loses electrons. It typically occurs when a substance reacts with oxygen. For example, when iron reacts with oxygen in the presence of water, it forms iron oxide (rust). This process is an example of oxidation.
1b. Reduction: Reduction is the opposite of oxidation. It is a chemical reaction in which a substance gains electrons. This reaction counteracts oxidation and is often referred to as deoxidation or reduction. For example, when iron oxide is heated with carbon, the carbon gains oxygen from the iron oxide, resulting in the reduction of iron oxide to pure iron.
5. (i) Rock type: Different types of rocks have different physical and chemical properties, which influence their susceptibility to weathering. For example, rocks that are composed of minerals that are more susceptible to chemical reactions may weather more quickly. Similarly, rocks that have a high porosity or contain cracks and fractures may be more susceptible to physical weathering processes like freeze-thaw cycles.
(ii) Slope: The slope of the land affects weathering because it influences the movement of water and other agents of weathering. Steep slopes allow water to flow more rapidly, increasing erosion and weathering rates. On the other hand, gentle slopes may lead to the accumulation of water, promoting chemical weathering and the action of organisms.
(iii) Climate: Climate plays a major role in weathering processes. In areas with high temperatures and abundant rainfall, chemical weathering is more pronounced. The presence of moisture and heat speeds up chemical reactions, leading to faster weathering rates. Additionally, freeze-thaw cycles are more common in colder climates, which can cause physical weathering.
c. (i) Geological factors: Geological factors such as the presence of fault lines, fractures, and joint systems can greatly influence erosion. These geological features provide pathways for water to flow, causing erosion along these paths. Additionally, the type and structure of underlying rock layers can affect erosion patterns. For example, if a layer of soft sediment overlays a layer of hard rock, erosion may occur more rapidly along the softer layer.
(ii) Overgrazing: Overgrazing occurs when livestock or wildlife consume vegetation at a rate higher than it can naturally regrow. This can lead to the removal of plants and their roots, which play a vital role in stabilizing the soil. Without vegetation, the soil becomes vulnerable to erosion by wind and water. Overgrazing can also reduce the vegetation cover, leading to increased runoff during rainfall events. This increased runoff can further contribute to erosion and the loss of topsoil.