Question

Acetylene gas has molecular formula how does the percent composition of acetylene compare with that of benzene

Answer 1

Acetylene has the molecular formula \(C_2H_2\) and benzene has the molecular formula \(C_6H_6\).

To calculate the percent composition of each compound, we first need to determine the molar mass of each:

### Molar Mass of Acetylene (\(C_2H_2\)):
- Carbon (C): \(12.01 \, \text{g/mol} \times 2 = 24.02 \, \text{g/mol}\)
- Hydrogen (H): \(1.01 \, \text{g/mol} \times 2 = 2.02 \, \text{g/mol}\)

**Total molar mass of acetylene**:
\(24.02 \, \text{g/mol} + 2.02 \, \text{g/mol} = 26.04 \, \text{g/mol}\)

**Percent composition of acetylene**:
- %C: \(\frac{24.02}{26.04} \times 100 \approx 92.24\%\)
- %H: \(\frac{2.02}{26.04} \times 100 \approx 7.76\%\)

### Molar Mass of Benzene (\(C_6H_6\)):
- Carbon (C): \(12.01 \, \text{g/mol} \times 6 = 72.06 \, \text{g/mol}\)
- Hydrogen (H): \(1.01 \, \text{g/mol} \times 6 = 6.06 \, \text{g/mol}\)

**Total molar mass of benzene**:
\(72.06 \, \text{g/mol} + 6.06 \, \text{g/mol} = 78.12 \, \text{g/mol}\)

**Percent composition of benzene**:
- %C: \(\frac{72.06}{78.12} \times 100 \approx 92.16\%\)
- %H: \(\frac{6.06}{78.12} \times 100 \approx 7.77\%\)

### Comparison:
- **Percent Composition of Acetylene**:
- \(C: 92.24\%\), \(H: 7.76\%\)
- **Percent Composition of Benzene**:
- \(C: 92.16\%\), \(H: 7.77\%\)

**Summary**:
- Acetylene has a slightly higher percentage of carbon (92.24%) compared to benzene (92.16%), while benzene has a marginally higher percentage of hydrogen (7.77%) compared to acetylene (7.76%). The differences are small but notable.