Physical properties
4 marks · NormalEthene, propene and butene are alkenes.
Complete the table to show the number of carbon (C) and hydrogen (H) atoms in each alkene.
| Alkene | Number of C atoms | Number of H atoms |
|---|---|---|
| Ethene | 2 | |
| Propene | ||
| Butene |
State the physical state (solid, liquid or gas) of these alkenes at room temperature.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) — · must show Ethene: C=2, H=4, Propene: C=3, H=6, Butene: C=4, H=8
(b) gas · must show gas
Common mistakes: Incorrect formula calculation; Incorrect state
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Marking points
B1 (a) · 1 mark · Ethene: number of H atoms correct (4)
B2 (a) · 1 mark · Propene: C=3, H=6 both correct
B3 (a) · 1 mark · Butene: C=4, H=8 both correct
B4 (b) · 1 mark · State 'gas' for all three at room temperature
Worked solution
| Alkene | Number of C atoms | Number of H atoms |
|---|---|---|
| Ethene | 2 | 4 |
| Propene | 3 | 6 |
| Butene | 4 | 8 |
All three alkenes are gases at room temperature.