Earth's Resources (GCSE Chemistry)

Earth’s Resources

Earth’s Resources

Using the Earth’s Resources

• Humans use the Earth’s resources. The resources on Earth are used by humans to give essentials such as warmth, food, shelter and transport. These resources are called natural resources.
• Some resources are finite. Finite resources are resources that will run out one day. They are also called non-renewable resources. These can also be used by humans to provide energy and materials.

Sustainable Development

• Chemistry can improve processes. We can use chemistry to improve agricultural and industrial processes. This can provide new products.
• Sustainable development looks after future generations. Through improving processes, we must develop sustainably. This meets the needs of the current generation without compromising the ability of the future generations to meet their own needs.
• Metal ores are natural resources. Sometimes, we use natural resources in order to develop sustainably. An example of a natural resource is a metal ore. Metal ores can be reduced down to create pure metals.

Extracting and Interpreting Information

• You must be able to extract information. By using charts, tables and graphs, you need to be able to extract information for exams.
• Tables can help you to identify materials. By looking at the information in a table, you can identify materials. For example, this could be by comparing the energy produced by two different materials.

Orders of Magnitude

• Orders of magnitude show data size. In Chemistry, we can use orders of magnitude to show the size of a data set that we are looking at. This can show the significance of the data.

Carbonates

Manufacture of Lime

Lime is a term used to describe either calcium oxide (quicklime) or calcium hydroxide (slaked lime).

Calcium carbonate (limestone) can undergo thermal decomposition to produce calcium oxide (quicklime). 

During thermal decomposition, the calcium carbonate is heated at 1000°C in a kiln. As calcium oxide is produced, calcium carbonate is  constantly replaced to keep the process going.

Manufacture of Slaked Lime

Above we learnt how calcium oxide can be manufactured. We can then use the calcium oxide to produce calcium hydroxide, or slaked lime.

Calcium oxide can react with water to form slaked lime in an exothermic reaction.

Uses of Quicklime and Slaked Lime

• Quicklime has many uses. It can be used to remove silica from a blast furnace. It is also used to neutralise acidic industrial waste products, for example in flue-gas desulphurisation. This is the process of removing sulphur dioxide and other emissions from fossil-fuel power stations.
• Slaked lime is also used to neutralise acids. The alkaline nature of slaked lime helps to reduce the acidity in soils and lakes, caused by acid rain. It is more expensive than powdered limestone, but acts faster.

Uses of Limestone

• Limestone is used to produce cement. Powdered limestone is heated with clay to produce cement. Cement can then be used to form both mortar and concrete. Mortar is formed by mixing cement, sand and water. Concrete is formed by cement, sand, water and aggregate.
• Limestone can help with strong bones and teeth. If added as a food additive, limestone can provide calcium ions to help in the formation of strong bones and teeth.
• Limestone can be used to reduce acidity. As mentioned before, limestone helps to reduce the acidity in soils and lakes caused by acid rain. It is cheaper than slaked lime but works slower.