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3.1 Define the term structural isomer - NSC Physical Sciences - Question 3 - 2016 - Paper 2
Question 3
3.1 Define the term structural isomer. 3.2 What type of isomers (POSITIONAL, CHAIN or FUNCTIONAL) are these three compounds? 3.3 Explain the trend in the boiling p... show full transcript
Worked Solution & Example Answer:3.1 Define the term structural isomer - NSC Physical Sciences - Question 3 - 2016 - Paper 2
Step 1
Define the term structural isomer.
Answer
Structural isomers are compounds that have the same molecular formula but differ in the arrangement of atoms within the molecule. This means they have different structural formulas, and as a result, may possess different physical and chemical properties.
Step 2
Step 3
Explain the trend in the boiling points from compound A to compound C.
Answer
The boiling points increase from compound A (2,2-dimethylpropane) to compound C (pentane). This trend can be attributed to the following:
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Structure: Compound A is less branched and more compact than compound C, leading to more effective packing and weaker intermolecular forces.
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Intermolecular Forces: Pentane has stronger London dispersion forces due to its larger surface area and more extensive molecular interactions compared to 2,2-dimethylpropane.
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Energy Required: As the strength of intermolecular forces increases, more energy is needed to overcome these forces, resulting in higher boiling points.
Step 4
Which ONE of the three compounds (A, B or C) has the highest vapor pressure?
Answer
Compound A (2,2-dimethylpropane) has the highest vapor pressure. This is because it has a lower boiling point compared to compounds B and C, which means it is more volatile and has a greater tendency to evaporate.
Step 5