Find the mass in grams of hydrogen gas produced when 14.0 moles of HCl is added to an excess amount of magnesium.

Answer;

14.0 g of hydrogen gas

Explanation;

The equation for the reaction is

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

From the equation, 2mol HCl will produce 1 mol H2

Moles of HCl = 14 moles

Therefore; 14 moles of HCl will produce 7 moles of hydrogen gas

1 mole of Hydrogen gas = 2.0 g/mol

Thus; mass of 7.0 moles of H2 = 7 * 2.0 g/mol

= 14.0 g