The following isomers are commonly used as fuels because of their low boiling points:
A Butane
B 2-methylpropane
3.1 Identify the homologous series to which these compounds belong - NSC Technical Sciences - Question 3 - 2024 - Paper 2
Question 3
The following isomers are commonly used as fuels because of their low boiling points:
A Butane
B 2-methylpropane
3.1 Identify the homologous series to which these ... show full transcript
Worked Solution & Example Answer:The following isomers are commonly used as fuels because of their low boiling points:
A Butane
B 2-methylpropane
3.1 Identify the homologous series to which these compounds belong - NSC Technical Sciences - Question 3 - 2024 - Paper 2
Step 1
3.1 Identify the homologous series to which these compounds belong.
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Answer
The compounds Butane (A) and 2-methylpropane (B) belong to the homologous series known as alkanes. Alkanes are characterized by having the general formula CnH2n+2, where n is the number of carbon atoms.
Step 2
3.2 Define the term structural isomers.
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Answer
Structural isomers are organic molecules that have the same molecular formula but differ in their structural arrangement. This means they have the same number of atoms of each element but connect in different ways, leading to different properties.
Step 3
3.3 What type of isomerism is represented by the compounds above?
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Answer
The type of isomerism represented by the compounds is chain isomerism. This occurs when compounds differ in the branching of their carbon skeletons.
Step 4
3.4 Identify the type of intermolecular forces in both compounds.
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Answer
Both butane and 2-methylpropane mainly experience London dispersion forces, which are a type of induced dipole-dipole interactions. These forces arise due to temporary fluctuations in electron distribution within molecules.
Step 5
3.5 Which ONE of the compounds has the strongest intermolecular forces? Write down only A or B.
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Answer
A
Step 6
3.6 Give a reason for the answer to QUESTION 3.5.
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Answer
Butane has stronger intermolecular forces than 2-methylpropane because it is a straight-chain compound, leading to more effective surface contact and thus stronger London dispersion forces compared to the more branched structure of 2-methylpropane.
Step 7
3.7 Define vapour pressure.
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Vapour pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its liquid or solid phase at a given temperature in a closed system. It is an indication of a substance's tendency to evaporate.
Step 8
3.8 Write down the compound above with a higher:
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Answer
3.8.1 Boiling point: Butane (A) has a higher boiling point than 2-methylpropane (B) due to its less branched structure, which allows for stronger intermolecular forces.
3.8.2 Vapour pressure: 2-methylpropane (B) has a higher vapour pressure than Butane (A) due to its branched structure, which causes weaker intermolecular forces.
