Chemistry-Using Reasources-Global reasources

What do humans use the Earth's resources for?

Shelter; food; warmth; transport.

What is meant by a finite resource?

A finite resource is one which cannot be replaced so will run out.

Define sustainable development.

Sustainable development is development that meets the needs of the current generations without compromising the ability of future generations to meet their own needs.

Give an example of a natural product that can be replaced by a synthetic product.

Rubber; fertiliser.

What is meant by a renewable resource?

Renewable resources are ones which can be replenished or replaced.

True or False? Wood is an example of a renewable resource.

True. Wood is an example of a renewable resource.

True or False? Rubber is an example of a synthetic product.

False. Rubber is an example of a natural resource as it is extracted from the sap of trees.

Define the term potable water.

Potable water is water that is safe to drink.

True or False? Potable water is pure water.

False. Potable water is not pure as it contains dissolved substances such as salts and chlorine.

Describe the two main steps used to produce potable water in the UK.

Filtration; sterilising.

Why is chlorine added to water?

Chlorine is added to water to kill bacteria.

Name three sterilising agents used to treat water.

Chlorine; UV light; ozone.

Why is water filtered when producing potable water?

Water is filtered to remove insoluble solids.

Define the term desalination.

Desalination is the removal of salt from water.

True or False? Distillation and reverse osmosis can remove salt from water.

True. Distillation and reverse osmosis can remove salt from water.

Why is distillation expensive?

Distillation is expensive because it requires large amounts of energy.

True or False? Potable water contains low levels of salts and microbes.

True. Potable water contains low levels of salts and microbes.

Give the main source of fresh water in the UK.

The main source of water in the UK is rain water collected in the ground, rivers and lakes.

Give two sources of waste water.

Industrial processes; sewage; agriculture.

Give the main steps involved in treating sewage.

Screening and grit removal; sedimentation; anaerobic digestion of sewage sludge; aerobic digestion of the effluent.

Why does sewage need to be treated?

Sewage needs to be treated to remove organic matter and harmful microbes.

Describe what happens during the sedimentation of sewage.

During the sedimentation of sewage, the water stands in a tank and the heavier solids sink to the bottom creating sewage sludge.

True or False? Aerobic digestion of the effluent requires oxygen.

True. Aerobic digestion of the effluent requires oxygen.

True or False? The effluent is treated by anaerobic digestion.

False. The effluent is treated by aerobic digestion.

What happens to the effluent once it has undergone aerobic digestion?

Once the effluent has undergone aerobic digestion the water is released back into the environment.

Why does sewage need to be screened?

Sewage needs to be screened to remove large solid materials.

What can the by-products of anaerobic digestion of sewage sludge be used for?

The by-products of anaerobic digestion of sewage sludge are used as fertiliser and methane as a source of energy.

Why does industrial waste water need to be treated?

Industrial waste water needs to be treated to remove organic matter and harmful chemicals.

True or False? There are unlimited amounts of metal ores. (Higher tier only)

False. There are limited amounts of metal ores.

What is meant by a low-grade ore? (Higher tier only)

A low-grade ore is one which contains a low concentration of the metal.

Name two methods used to extract copper from low-grade ores. (Higher tier only)

Bioleaching and phytomining.

Describe how bioleaching is used to extract copper from low-grade ores. (Higher tier only)

Bioleaching is used to extract copper from low-grade ores by using bacteria to produce a leachate solution that contains metal compounds.

Describe how phytomining is used to extract copper from low-grade ores. (Higher tier only)

The plant absorbs copper through the roots; the plant is harvested, dried and burned; the metal compound is collected from the ash; the metal is obtained from its compound by displacement or electrolysis.

Give a disadvantage of using biological methods to extract metals from low-grade ores. (Higher tier only)

The process is slow; sometimes electrolysis is used to purify the extracted metal which uses energy.

True or False? Copper is obtained from a solution of its compound by displacement using lead. (Higher tier only)

False. Copper is obtained from a solution of its compound by displacement using scrap iron because it is cheap.

Name two methods used to extract copper from the copper compound obtained from phytomining or bioleaching. (Higher tier only)

Displacement using scrap iron; electrolysis.

Write the symbol equation for the displacement reaction between copper sulfate and iron, including state symbols. (Higher tier only)

CuSO4 (aq) + Fe (s) → FeSO4 (aq) + Cu (s)

True or False? Phytomining and bioleaching are not just used to extract copper from low-grade ores. (Higher tier only)

True. Phytomining and bioleaching are not just used to extract copper from low-grade ores, they can be used to extract other metals but they are mainly used for copper due to its high global demand.

Give an advantage of using biological methods to extract metals from low-grade ores. (Higher tier only)

Conserves high-grade ores; avoids the large amount of digging, moving and disposing of rock involved in traditional mining; conserves energy; less pollution.

Why is it necessary to extract copper from low-grade ores? (Higher tier only)

It is necessary to extract copper from low-grade ores because high-grade copper ores are becoming scarce.