A chemist reacts 30.0 mL of 5.6 M HCl with an excess of Mg (OH) 2. How many grams of magnesium chloride will be produced?

First set-up a balanced chemical equation:

2HCl + Mg (OH) 2 - - - > MgCl2 + 2H2O

Given: 30mL of 5.6M HCl and excess of Mg (OH) 2

To determine the amount of magnesium chloride produced:

MgCl2 (g) = (30mL * (1L / 1000mL) * 5.6 mol/L) * (1 mol MgCl2 / 2 mol HCl) * (94.9 g / mol MgCl2)

MgCl2 (g) = 7.97 g