A hydrocarbon has an empirical formula of CH2. Its density at r.t.p. is 0.001167 g/cm3. [1] a) Determine the molecular formula of the hydrocarbon. [1] b) Draw the structural formula of the hydrocarbon

The atomic mass of Carbon (C) is 12.0 and Hydrogen (H) is 1.0.

$$\text{EFM} = (1 \times 12.0) + (2 \times 1.0) = 12.0 + 2.0 = 14.0 \text{ g/mol}$$

First, convert the density from $\text{g/cm}^3$ to $\text{g/dm}^3$.

$$1 \text{ dm}^3 = 1000 \text{ cm}^3$$ $$\text{Density} = 0.001167 \text{ g/cm}^3 \times 1000 \text{ cm}^3/\text{dm}^3 = 1.167 \text{ g/dm}^3$$

Now, calculate the molar mass (M).

$$\text{Molar Mass} = \text{Density} \times \text{Molar Gas Volume}$$ $$\text{Molar Mass} = 1.167 \text{ g/dm}^3 \times 24 \text{ dm}^3/\text{mol} = 28.008 \text{ g/mol}$$

$$n = \frac{\text{Molar Mass}}{\text{Empirical Formula Mass}}$$ $$n = \frac{28.008 \text{ g/mol}}{14.0 \text{ g/mol}} = 2.00057 \approx 2$$

$$\text{Molecular Formula} = (\text{Empirical Formula})_n$$ $$\text{Molecular Formula} = (\text{CH}_2)_2 = \text{C}_2\text{H}_4$$

The molecular formula of the hydrocarbon is $\boxed{\text{C}_2\text{H}_4}$.