Organic chemistry - Naming organic compounds (3)
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1.
State the type of compound present in each of the following chemical names:
- a) Pentane
- b) Ethene
- c) Ethanol
- d) Propanoic acid
a) Pentane: Alkane - Contains only single bonds between carbon atoms.
b) Ethene: Alkene - Contains a carbon-carbon double bond.
c) Ethanol: Alcohol - Contains a hydroxyl (-OH) group attached to a carbon atom.
d) Propanoic acid: Carboxylic acid - Contains a carboxyl (-COOH) group.
2.
A molecule has the molecular formula C4H8. State the type of compound it is.
The molecular formula C4H8 indicates a hydrocarbon containing four carbon atoms and eight hydrogen atoms. This ratio suggests the presence of a double bond. Therefore, the compound is an alkene.
3.
Question 1
Name and draw the structural formulae and write the displayed formulae of the following unbranched organic compounds:
- (a) Alkanes
- (b) Alkenes, including but-1-ene and but-2-ene
- (c) Alcohols, including propan-1-ol, propan-2-ol, butan-1-ol and butan-2-ol
Answer 1
(a) Alkanes:
The general formula for alkanes is CnH2n+2. A few examples are:
- Methane (n=1): Structure: CH4, Displayed: CH4
- Ethane (n=2): Structure: CH3CH3, Displayed: CH3CH3
- Propane (n=3): Structure: CH3CH2CH3, Displayed: CH3CH2CH3
- Butane (n=4): Structure: CH3CH2CH2CH3, Displayed: CH3CH2CH2CH3
(b) Alkenes:
Alkenes contain a carbon-carbon double bond.
- But-1-ene: Structure: CH2=CHCH2CH3, Displayed: CH2=CHCH2CH3
- But-2-ene: Structure: CH3CH=CHCH3, Displayed: CH3CH=CHCH3
(c) Alcohols:
Alcohols contain a hydroxyl (-OH) group.
- Propan-1-ol: Structure: CH3CH2CH2OH, Displayed: CH3CH2CH2OH
- Propan-2-ol: Structure: CH3CH(OH)CH3, Displayed: CH3CH(OH)CH3
- Butan-1-ol: Structure: CH3CH2CH2CH2OH, Displayed: CH3CH2CH2CH2OH
- Butan-2-ol: Structure: CH3CH(OH)CH2CH3, Displayed: CH3CH(OH)CH2CH3