When 24.3 g of magnesium reacts completely with excess hydrochloric acid according to the equation Mg + 2HCl → MgCl_2 + H_2, how many grams of magnesium chloride (MgCl_2) are produced?

• A. 48.6 g
• B. 40.3 g
• C. 95.2 g
• D. 24.3 g

Answer: (C)

Verified step by step guidance

1. Write down the balanced chemical equation: \(\mathrm{Mg} + 2\mathrm{HCl} \rightarrow \mathrm{MgCl}_2 + \mathrm{H}_2\).
2. Calculate the molar mass of magnesium (Mg). Use the atomic mass from the periodic table, approximately 24.3 g/mol.
3. Convert the given mass of magnesium (24.3 g) to moles using the formula: \(\text{moles of Mg} = \frac{\text{mass of Mg}}{\text{molar mass of Mg}}\).
4. Use the stoichiometric ratio from the balanced equation to find moles of magnesium chloride (\(\mathrm{MgCl}_2\)). Since 1 mole of Mg produces 1 mole of \(\mathrm{MgCl}_2\), moles of \(\mathrm{MgCl}_2\) = moles of Mg.
5. Calculate the mass of \(\mathrm{MgCl}_2\) produced by multiplying the moles of \(\mathrm{MgCl}_2\) by its molar mass. The molar mass of \(\mathrm{MgCl}_2\) is calculated by adding the atomic masses of 1 Mg and 2 Cl atoms: \(\mathrm{MgCl}_2 = 24.3 + 2 \times 35.45\) g/mol. Then, \(\text{mass of } \mathrm{MgCl}_2 = \text{moles of } \mathrm{MgCl}_2 \times \text{molar mass of } \mathrm{MgCl}_2\).