This question is about combustion of fuels. Some central heating boilers use wood as a fuel. Suggest two reasons why wood is more sustainable than natural gas as a fuel for central heating boilers. 1 2 Natural gas is mainly methane. When methane burns it can produce both carbon monoxide and carbon dioxide. Explain the process by which carbon monoxide can be produced when methane is burned. Balance the equation for the combustion of methane to produce carbon monoxide. ___ CH4(g) + ___ O2(g) → ___ CO(g) + ___ H2O(l) Propane burns to form carbon dioxide and water. The equation for the reaction is: C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l) 3.60 dm³ carbon dioxide is produced when a sample of propane is burned in 7.25 dm³ oxygen. Calculate the volume of unreacted oxygen. Give your answer in cm³

GCSE AQA Chemistry Hydrocarbons: Fuel & Feedstock: This question is about combustio

This question is about combustion of fuels - AQA - GCSE Chemistry - Question 5 - 2019 - Paper 2

Question 5

This question is about combustion of fuels. Some central heating boilers use wood as a fuel. Suggest two reasons why wood is more sustainable than natural gas as a... show full transcript

Worked Solution & Example Answer:This question is about combustion of fuels - AQA - GCSE Chemistry - Question 5 - 2019 - Paper 2

Step 1

Suggest two reasons why wood is more sustainable than natural gas as a fuel for central heating boilers.

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Answer

Wood is renewable, as it can be replanted and sourced sustainably without depleting resources.
The burning of wood is considered carbon-neutral, as it releases the same amount of carbon dioxide that the trees absorbed during their growth, therefore not contributing to global warming.

Step 2

Explain the process by which carbon monoxide can be produced when methane is burned.

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Answer

Carbon monoxide is produced during the incomplete combustion of methane ( ext{CH}_4) when there is insufficient oxygen available. Instead of converting all carbon to carbon dioxide ( ext{CO}_2), some carbon is released as carbon monoxide ( ext{CO}) due to inadequate oxygen supply, leading to the reaction:

ightarrow ext{CO} + 2 ext{H}_2 ext{O}$$

Step 3

Balance the equation for the combustion of methane to produce carbon monoxide.

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Answer

The balanced equation is:

ightarrow 2 ext{CO}(g) + 4 ext{H}_2 ext{O}(l)$$

Step 4

Calculate the volume of unreacted oxygen.

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Answer

From the stoichiometry of the reaction:

The balanced reaction shows that the mole ratio of ext{O}_2 to ext{CO}_2 is 5:3.
Since 3.60 dm³ of ext{CO}_2 is produced, the amount of ext{O}_2} needed is:

$ext{O}_2 ext{ needed} = rac{3.60 ext{ dm}^3 imes 5}{3} = 6.0 ext{ dm}^3$

Given that 7.25 dm³ of ext{O}_2 was used, the volume of unreacted ext{O}_2 is:

$ext{Volume of unreacted } ext{O}_2 = 7.25 ext{ dm}^3 - 6.0 ext{ dm}^3 = 1.25 ext{ dm}^3$

Finally, converting this to cm³:

$1.25 ext{ dm}^3 = 1250 ext{ cm}^3$

This question is about combustion of fuels - AQA - GCSE Chemistry - Question 5 - 2019 - Paper 2

Worked Solution & Example Answer:This question is about combustion of fuels - AQA - GCSE Chemistry - Question 5 - 2019 - Paper 2

Suggest two reasons why wood is more sustainable than natural gas as a fuel for central heating boilers.

Explain the process by which carbon monoxide can be produced when methane is burned.

Balance the equation for the combustion of methane to produce carbon monoxide.

Calculate the volume of unreacted oxygen.

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