Alternative methods of extracting metals

Gold is used in the printed circuit boards found in smartphones.

Figure 6 shows a printed circuit board.

A type of smartphone contains 1.73 × 10^–4 moles of gold.

In one year, a manufacturer sold 2.48 million of this type of smartphone.

Calculate the total mass of gold contained in 2.48 million of these smartphones.

Give your answer in kilograms.

Relative atomic mass (A_r): Au = 197

What is the total number of gold atoms in one of this type of smartphone?

The Avogadro constant = 6.02 × 10²³ per mole

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The materials in printed circuit boards can be recycled.

Bioleaching is one method used to extract gold from printed circuit boards.

Describe how bioleaching is used to extract gold.

Copper is also extracted using bioleaching.

Copper can also be extracted from low-grade ores using phytomining.

Phytomining has not been widely used to extract copper.

Suggest two reasons why.

The Earth’s natural resources are used to manufacture useful products.

One useful product is potable water.

Potable water can be produced from sea water by distillation.

Give one disadvantage of using distillation to produce potable water.

Describe one other method to produce potable water from sea water.

A student investigated the mass of dissolved solids in a 100 cm³ sample of

sea water.

This is the method used.

1. Weigh an evaporating basin.

2. Measure 100 cm³ of sea water.

3. Pour the sea water into the evaporating basin.

4. Heat the evaporating basin.

5. Weigh the evaporating basin and contents.

6. Calculate the mass of dissolved solids in the sea water.

Explain how repeating steps 4 and 5 would improve this method.

The total mass of dissolved solids in a 100 cm³ sample of sea water is 3.50 g.

The percentage of sodium chloride in the dissolved solids is 77.8%.

Calculate the mass of sodium chloride dissolved in the 100 cm³ sample of sea water.

Biological methods are used to extract metal compounds from metal ores.

One method of producing copper from low-grade copper ores is by using bacteria.

The bacteria produce leachate solutions that contain copper compounds.

Give two methods that can be used to extract copper from these leachate solutions.

Phytomining uses plants to absorb metal compounds from low-grade ores.

Describe how the metal compounds are obtained from the plants.

Nickel is produced by phytomining.

One hectare of plants produces 215 kg of nickel.

Determine the area required to produce 750 kg of nickel.

Give your answer in m².

This question is about the Earth’s atmosphere and the Earth’s resources.

After the formation of the Earth’s early atmosphere, the amounts of nitrogen and oxygen in the atmosphere changed. Explain the main changes in the amounts of nitrogen and oxygen in the Earth’s atmosphere.

Describe how coal was formed from the carbon dioxide present in the Earth’s early atmosphere.

The combustion of 1.0 kg of coal produces more carbon dioxide than the combustion of 1.0 kg of natural gas. Suggest why.

Metals are extracted from metal ores found in the Earth.

Describe how bioleaching is used to extract copper from low grade ores.

Phytomining uses plants to extract nickel from low grade ores. The plants contain 0.792% nickel by mass. The plants are burned to produce ash. The ash from these plants contains 4.80% nickel by mass. Calculate the mass of ash produced from burning 1000 kg of plants. Give your answer in grams in standard form.

Industries use the Earth’s natural copper resources to produce useful products.

Figure 4 shows the world production of copper from 1900 to 2020.

Describe the trend shown by the graph in Figure 4.

Suggest one reason for the trend in Figure 4.

Suggest one reason why the trend cannot be used to accurately predict the future world production of copper.

High-grade copper resources are now difficult to find.

Phytomining is used to extract copper from low-grade ores.

There are five stages, A, B, C, D and E, in phytomining.

The stages are not in the correct order.

Stage A Copper compounds from ash are dissolved in acid.

Stage B Plants absorb metal compounds.

Stage C Plants are burned.

Stage D Plants are harvested.

Stage E Solution of copper compound is electrolysed.

What is the correct order of stages A, B, C, D, and E ?

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Give two disadvantages of phytomining compared with traditional mining methods.

Do not refer to cost in your answer.

In one year, 8.89 × 10⁹ kg of copper was produced.

41.0% of this copper was produced from recycled copper.

The energy needed to produce 1 kg of copper from copper ore is 70.4 MJ.

The energy needed to produce 1 kg of recycled copper is 27.2 MJ.

Calculate the difference in energy used if all the copper was produced from recycling.

Give your answer to 3 significant figures.

This question is about copper and fuels.

Copper is extracted from low-grade ores by phytomining. Describe how copper metal is produced by phytomining.

Another method of extracting copper from low-grade ores is bioleaching. A solution of copper sulfate (CuSO₄) produced by bioleaching has a

Relative atomic masses (A_r): Cu = 63.5 O = 16 S = 32 Calculate the number of moles of copper that can be produced from 1 dm³ of this solution.

Copper is used as a catalyst. Figure 1 shows reaction profiles for a reaction with and without a catalyst.

How do the reaction profiles show that using a catalyst does not affect the overall energy change for the reaction?

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Copper is a catalyst in a reaction to produce ethanol from carbon dioxide. Ethanol (C₂H₅OH) is used as a fuel. Suggest why producing ethanol from carbon dioxide is sustainable.

Chemistry plays an important role in sustainable development. What is sustainable development?