Answer to Question #279981 in General Chemistry for Jade

Question

b. What is the mass in grams of H2 when 4.0 moles of HCl is added to the reaction?

Answer 1

The reaction is:

Mg(s) + 2HCl(aq) = MgCl2(aq) + H2(g)

The chemical equation shows that: 1 mole of Mg + 2 moles of HCl = 1 mole of H2 + 1 mole of MgCl2

Moles of $H_2=\frac{4.0}{2}=2.0moles$

The molar mass of hydrogen gas is 2.016 grams per mole

Mass$=2.016×2=4.032grams$