The table below lists six organic compounds, labeled P to U, and shows their structures or formulas:
| Letter | Compound Name / Structure |
|---|---|
| P | Ethane, CH3CH3\text{CH}_3\text{CH}_3CH3CH3 |
| Q | Propene, CH3CH=CH2\text{CH}_3\text{CH}=\text{CH}_2CH3CH=CH2 |
| R | Propane, CH3CH2CH3\text{CH}_3\text{CH}_2\text{CH}_3CH3CH2CH3 |
| S | Pent-2-ene, CH3CH=CHCH2CH3\text{CH}_3\text{CH}=\text{CHCH}_2\text{CH}_3CH3CH=CHCH2CH3 |
| T | Cyclopentane, a cyclic molecule containing a ring of five CH2\text{CH}_2CH2 groups |
| U | Hexane, CH3CH2CH2CH2CH2CH3\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{CH}_2\text{CH}_3CH3CH2CH2CH2CH2CH3 |
Explain why all of these compounds are described as hydrocarbons.
Why are Q and S described as unsaturated?
Which letter represents the member of the homologous series of alkanes with two carbon atoms?
Which letters represent compounds that have the empirical formula CH2\text{CH}_2CH2?
Compound T has the same general formula as an alkene. Why does T not decolourise bromine water?
One of the compounds in the table reacts with bromine to form H, a compound with the percentage composition by mass: C=29.5%\text{C} = 29.5\%C=29.5%, H=4.9%\text{H} = 4.9\%H=4.9%, Br=65.6%\text{Br} = 65.6\%Br=65.6%. (Relative atomic masses: C=12\text{C} = 12C=12, H=1\text{H} = 1H=1, Br=80\text{Br} = 80Br=80)
Show, by calculation, that the empirical formula of H is C3H6Br\text{C}_3\text{H}_6\text{Br}C3H6Br.
The relative formula mass of H is 244. Deduce the molecular formula of H.
