This question is about fuels. The petrol fraction obtained from crude oil can be used as fuel in cars. State the meaning of fraction, as used in the term petrol fraction. Hexadecane (C₁₆H₃₄) can be cracked at high temperature to form petrol. Complete the equation to show the cracking of one molecule of hexadecane to form hexane and cyclopentane only. Give the name of a catalyst used in this cracking reaction. Carbon dioxide is formed when petrol is burned. Carbon dioxide acts as a greenhouse gas when it absorbs infrared radiation. Give a reason why carbon dioxide absorbs infrared radiation. Compound Z (HOCH₂CH₂NH₂) can be used to remove carbon dioxide from the mixture of waste gases produced in some power stations. Figure 1 shows part of a suggested mechanism for the reaction of Z with carbon dioxide. Draw two curly arrows to complete the mechanism in Figure 1. Name compound Z (HOCH₂CH₂NH₂). Deduce the role of Z in step 2 of the mechanism. Draw the shape of XNH₂. [HOCH₂CH₂NH₂]⁻ can be represented as [XNH₃]. Explain your answer. Bond angle Explanation Bioethanol is used as an alternative to fossil fuels. This statement appeared on a website. "The fact that bioethanol is a carbon-neutral fuel outweighs the environmental disadvantages of producing bioethanol." Evaluate this statement. In your answer you should include: - an outline of how bioethanol is produced - relevant equations - analysis of the environmental impacts.

Photo AI

This question is about fuels - AQA - A-Level Chemistry - Question 2 - 2021 - Paper 2

Question 2

This question is about fuels. The petrol fraction obtained from crude oil can be used as fuel in cars. State the meaning of fraction, as used in the term petrol fr... show full transcript

Worked Solution & Example Answer:This question is about fuels - AQA - A-Level Chemistry - Question 2 - 2021 - Paper 2

Step 1

State the meaning of fraction, as used in the term petrol fraction.

96%

114 rated

Answer

In the context of fuels, a fraction refers to a specific range of hydrocarbons that have similar boiling points and can be separated during the refinement of crude oil.

Step 2

Complete the equation to show the cracking of one molecule of hexadecane to form hexane and cyclopentane only.

99%

104 rated

Answer

C₁₆H₃₄ → C₆H₁₄ + C₅H₁₂

Step 3

Give the name of a catalyst used in this cracking reaction.

96%

101 rated

Answer

A common catalyst used in cracking reactions is zeolite.

Step 4

Give a reason why carbon dioxide absorbs infrared radiation.

98%

120 rated

Answer

Carbon dioxide molecules possess vibrational modes that can absorb infrared radiation, which contributes to the greenhouse effect.

Step 5

Draw two curly arrows to complete the mechanism in Figure 1.

97%

117 rated

Answer

Curly arrows should be drawn from the lone pair on the nitrogen in Z to the carbon of CO₂, and from the C=O bond in CO₂ to the oxygen atom, indicating the formation of a bond and the breakdown of the double bond.

Step 6

Name compound Z (HOCH₂CH₂NH₂).

97%

121 rated

Answer

Compound Z is known as 2-aminoethanol (or ethylene glycol amine).

Step 7

Deduce the role of Z in step 2 of the mechanism.

96%

114 rated

Answer

In step 2 of the mechanism, Z acts as a base, accepting a proton to facilitate the reaction with carbon dioxide.

Step 8

Draw the shape of XNH₂.

99%

104 rated

Answer

The shape of XNH₂ (amine) is trigonal pyramidal due to the presence of a lone pair on nitrogen.

Step 9

[HOCH₂CH₂NH₂]⁻ can be represented as [XNH₃]. Explain your answer.

96%

101 rated

Answer

XNH₃ indicates a rigid tetrahedral shape with bond angles of approximately 107 degrees due to the lone pair-bond pair repulsion, being greater than the angles seen in a tetrahedral configuration.

Step 10

Bond angle

98%

120 rated

Answer

Approximately 107 degrees.

Step 11

Explanation

97%

117 rated

Answer

The bond angle is affected by the presence of the lone pair on nitrogen, which pushes the H-N-H bond angles down from the ideal tetrahedral angle (109.5 degrees) to about 107 degrees.

Step 12

Evaluate the statement regarding bioethanol.

97%

121 rated

Answer

Bioethanol is produced through fermentation of sugars, typically from corn or sugarcane. When burned, it releases CO₂, which is nearly equal to the amount absorbed during its growth, positioning it as a carbon-neutral fuel. However, concerns arise about land use, production emissions, and its impact on food supply. Thus, while its carbon neutrality is a positive aspect, potential negative environmental impacts cannot be overlooked.

Join the A-Level students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

This question is about fuels - AQA - A-Level Chemistry - Question 2 - 2021 - Paper 2

Worked Solution & Example Answer:This question is about fuels - AQA - A-Level Chemistry - Question 2 - 2021 - Paper 2

State the meaning of fraction, as used in the term petrol fraction.

Complete the equation to show the cracking of one molecule of hexadecane to form hexane and cyclopentane only.

Give the name of a catalyst used in this cracking reaction.

Give a reason why carbon dioxide absorbs infrared radiation.

Draw two curly arrows to complete the mechanism in Figure 1.

Name compound Z (HOCH₂CH₂NH₂).

Deduce the role of Z in step 2 of the mechanism.

Draw the shape of XNH₂.

[HOCH₂CH₂NH₂]⁻ can be represented as [XNH₃]. Explain your answer.

Bond angle

Explanation

Evaluate the statement regarding bioethanol.

Join the A-Level students using SimpleStudy...

Other A-Level Chemistry topics to explore