Compound A contains carbon, hydrogen and oxygen. Analysis of 0.44 g of A gave 0.88 g of carbon dioxide and 0.36 g of water on completion of combustion in oxygen. (i) Determine the empirical formula of A. (ii) Given that the Molar Mass of A is 44 g/mol, determine its molecular formula. (iii) How can the presence of carbon in compound A be identified?

$$\begin{align*} \mathrm{C}: &\quad \frac{3.33}{3.33} = 1\\ \mathrm{H}: &\quad \frac{6.7}{3.33} = 2.01 \approx 2\\ \mathrm{O}: &\quad \frac{3.33}{3.33} = 1 \end{align*}$$

Empirical formula = $\mathbf{CH_2O}$ $\boxed{\ce{CH2O}}$

3(b) Molecular formula (molar mass = $60~\mathrm{g/mol}$)

$$n = \frac{60}{30} = 2$$

Molecular formula = $\ce{(CH2O)_2} = \mathbf{C_2H_4O_2}$ $\boxed{\ce{C2H4O2}}$

3(c) Name of compound A

$\mathbf{\ce{CH3COOH},~\text{acetic acid (ethanoic acid)}}$ $\boxed{\ce{CH3COOH}}$

2. True or false: Carbon always shows 4 covalent bonds

True (Carbon has 4 valence electrons and forms 4 covalent bonds to achieve octet stability.)