For the compounds listed above, write down the:
3.1.1 Structural formula of compound F
3.1.2 LETTER that represents a POSITIONAL isomer of compound E
3.1.3 LETTER that represents a CHAIN isomer of compound E
The boiling points increase from compound A to compound D - NSC Physical Sciences - Question 3 - 2017 - Paper 2
Question 3
For the compounds listed above, write down the:
3.1.1 Structural formula of compound F
3.1.2 LETTER that represents a POSITIONAL isomer of compound E
3.1.3 LETT... show full transcript
Worked Solution & Example Answer:For the compounds listed above, write down the:
3.1.1 Structural formula of compound F
3.1.2 LETTER that represents a POSITIONAL isomer of compound E
3.1.3 LETTER that represents a CHAIN isomer of compound E
The boiling points increase from compound A to compound D - NSC Physical Sciences - Question 3 - 2017 - Paper 2
Step 1
3.1.1 Structural formula of compound F
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Answer
The structural formula for compound F (2-methylpropan-1-ol) can be illustrated as follows:
H H H
| | |
H - C - C - C - OH
| |
H H
This structure shows the functional group (-OH) bonded to the first carbon in the chain.
Step 2
3.1.2 LETTER that represents a POSITIONAL isomer of compound E
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Answer
The positional isomer of compound E (butan-2-ol) is represented by the letter D.
Step 3
3.1.3 LETTER that represents a CHAIN isomer of compound E
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Answer
The chain isomer of compound E is represented by the letter G.
Step 4
3.2.1 Give a reason for this increase in terms of the molecular structure.
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Answer
The increase in boiling points from compound A to compound D can be attributed to the increase in chain length and, consequently, the molecular size. As the molecular structure becomes larger, there is an increase in surface area, which enhances the van der Waals forces (dispersion forces) between molecules.
Step 5
3.2.2 Name the intermolecular force in these compounds responsible for this increase.
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The intermolecular forces responsible for this increase in boiling points are London dispersion forces (also known as van der Waals forces).
Step 6
3.3.1 From these boiling points, choose the boiling point represented by Y in the table above.
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Answer
The boiling point represented by Y is 108 °C.
Step 7
3.3.2 Fully explain how you arrived at the answer to QUESTION 3.3.1.
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I arrived at the answer by analyzing the boiling points of the given compounds. The boiling points increase with molecular size, and by comparing the most likely patterns, the boiling point of the compound with a molecular weight that would fit between the other values in the table indicates that Y corresponds to 108 °C.
Step 8
Draw two structural formula of compound A.
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Answer
The two structural formulas for compound A (methanol) can be shown as:
H H
| |
H - C - O - H
|
H
H H
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H - C - O - H
|
H
Using a dotted line to indicate hydrogen bonding:
H H H H
| | | |
H - C - O - H . . . . H - C - O - H
|
H
Step 9
3.5.1 Type of reaction that takes place
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The reaction that takes place is an esterification reaction.
Step 10
3.5.2 Structural formula of the organic product formed.
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Answer
The structural formula of the organic product formed can be illustrated as:
O
||
H - C - O - C - H
| |
H H
This shows the ester formed from the reaction of compound B with propanoic acid.
