How many structural isomers have the molecular formula \(\ce{C3H6BrCl}\)?
- 4
- 5
- 6
- 7
CHEMISTRY, M7 2023 HSC 8 MC
How many structural isomers have the molecular formula \( \ce{C3H6F2} \)?
- 2
- 3
- 4
- 5
Show Worked Solution
→ Structural Isomers will have the same molecular formula but different structures.
→ The fluoride Ions can exists at different points on the carbon chain, changing the name and structure of the compound without altering its molecular formula.
\(\Rightarrow C\)
♦ Mean mark 53%.
CHEMISTRY, M7 2023 HSC 21
Some isomers with the formula \( \ce{C4H8O} \) are shown.
Name ONE pair of functional group isomers and ONE pair of chain isomers from the structures above. (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
CHEMISTRY, M7 EQ-Bank 25
Draw the structural formulae and name all possible isomers of hexane. (3 marks)
--- 7 WORK AREA LINES (style=lined) ---
Show Answers Only
Show Worked Solution
CHEMISTRY, M7 2018 HSC 14 MC
How many isomers are there of \(\ce{C3H6ClF}\)?
- 3
- 4
- 5
- 6
Show Worked Solution
`=>C`
♦♦ Mean mark 39%.
CHEMISTRY, M7 2019 HSC 21
- The structural formula for 2-methylpropan-2-ol is shown in the table.
- Draw one structural isomer of this alcohol and state its name. (2 marks)
--- 0 WORK AREA LINES (style=blank) ---
- The structural formulae for two compounds are shown below.
- Why are these two compounds classed as functional group isomers? (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
- A chemical test is required to distinguish between the isomers in part (b).
- Identify a suitable test and explain the expected observations. (3 marks)
--- 6 WORK AREA LINES (style=lined) ---
Show Answers Only
a. Successful answers should have one of the following:
b. Functional Group isomers
→ Both isomers have the same number and type of atoms, but they have different arrangements of those atoms and therefore have different functional groups.
→ Isomer A has a ketone functional group, while isomer B has an aldehyde functional group.
c. Tollens’ Test:
→ The Tollens’ test can be used to differentiate between Isomer A (a ketone) and Isomer B (an aldehyde).
→ Isomer B will be readily oxidised to a carboxylic acid, whereas isomer A will not.
→ As a result, Isomer B will reduce the silver-ions in Tollens’ reagent to form a silver mirror inside the test tube, while Isomer A will not react.
Show Worked Solution
a. Successful answers should have one of the following:
b. Functional Group isomers
→ Both isomers have the same number and type of atoms, but they have different arrangements of those atoms and therefore have different functional groups.
→ Isomer A has a ketone functional group, while isomer B has an aldehyde functional group.
c. Tollens’ Test:
→ The Tollens’ test can be used to differentiate between Isomer A (a ketone) and Isomer B (an aldehyde).
→ Isomer B will be readily oxidised to a carboxylic acid, whereas isomer A will not.
→ As a result, Isomer B will reduce the silver-ions in Tollens’ reagent to form a silver mirror inside the test tube, while Isomer A will not react.
♦♦ Mean mark (c) 39%.
CHEMISTRY, M7 2020 HSC 7 MC
The structures of four isomers are shown.
Which statement is correct?
- Compounds 1 and 2 are chain isomers.
- Compounds 1 and 4 are chain isomers.
- Compounds 2 and 3 are functional group isomers.
- Compounds 2 and 4 are positional isomers.
CHEMISTRY, M8 2022 HSC 27
A bottle labelled 'propanol' contains one of two isomers of propanol.
- Draw the TWO isomers of propanol. (2 marks)
- Describe how \( \ce{^13C NMR}\) spectroscopy might be used to identify which isomer is in the bottle. (2 marks)
--- 6 WORK AREA LINES (style=lined) ---
- Each isomer produces a different product when oxidised.
- Write equations to represent the oxidation reactions of the two isomers. Include reaction conditions. (3 marks)
--- 6 WORK AREA LINES (style=lined) ---
Show Answers Only
a. Isomer 1:
Isomer 2:
b. Identifying isomers with \( \ce{^13C NMR} \) spectroscopy:
→ this can be used to identify the isomers in the bottle because they show a different number of signals which helps deduce the carbon environment.
→ Propan-1-ol contains 3 \( \ce{C}\) environments so it would have 3 peaks on a \( \ce{^13C NMR}\) spectrum whereas propan-2-ol only contains 2 \( \ce{C}\) environments (due to symmetry), so it would only have 2 signals on a \( \ce{^13C NMR}\) spectrum.
c.
Show Worked Solution
a. Isomer 1:
Isomer 2:
b. Identifying isomers with \( \ce{^13C NMR} \) spectroscopy:
→ this can be used to identify the isomers in the bottle because they show a different number of signals which helps deduce the carbon environment.
→ Propan-1-ol contains 3 \( \ce{C}\) environments so it would have 3 peaks on a \( \ce{^13C NMR}\) spectrum whereas propan-2-ol only contains 2 \( \ce{C}\) environments (due to symmetry), so it would only have 2 signals on a \( \ce{^13C NMR}\) spectrum.
c.
♦ Mean mark (c) 52%.
CHEMISTRY, M7 2021 HSC 24
A straight-chained alkane has a molar mass of 72.146 g mol ¯1.
Provide the structural formulae for this alkane and all of its isomers.
Name these molecules using IUPAC conventions. (4 marks)
--- 8 WORK AREA LINES (style=lined) ---
Show Answers Only
Straight chained alkane (Pentane):
2-methylbutane:
2,2-dimethylpropane:
Show Worked Solution
Straight chained alkane (Pentane):
2-methylbutane:
2,2-dimethylpropane: