## Chemistry: Molecular Approach (4th Edition)

1. Calculate the number of moles of $Mg(OH)_2$: 24.31* 1 + 2 * ( 16* 1 + 1.008* 1 ) = 58.326g/mol $3.26g \times \frac{1 mol}{ 58.326g} = 0.05589mol (Mg(OH)_2)$ According to the balanced equation: The ratio of $Mg(OH)_2$ to $HCl$ is 1 to 2: $0.05589 mol (Mg(OH)_2) \times \frac{ 2 mol(HCl)}{ 1 mol (Mg(OH)_2)} = 0.1118mol (HCl)$ 2. Calculate the mass of $HCl$: 1.008* 1 + 35.45* 1 = 36.46g/mol $0.1118 mol \times \frac{ 36.46 g}{ 1 mol} = 4.08g (HCl)$