Question

1.92 g of zinc metal reacts with excess hydrochloric acid to produce hydrogen gas. What volume (L) of hydrogen is generated at STP?

Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H₂(g)
O 0.719
O 6.03 10:2
O 0.656
O 47.0
O 43.1

Answer 1

1.92 g of zinc reacts with excess hydrochloric acid to produce 0.658 L of hydrogen gas at STP, based on the stoichiometry of the reaction and the molar volume of a gas at STP. The correct answer is near to the option c.

Step-by-step explanation:

When 1.92 g of zinc metal reacts with excess hydrochloric acid, the balanced chemical equation is:
Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g). The molar mass of zinc (Zn) is 65.38 g/mol. To find how many moles of Zn we have, we divide the mass of zinc by its molar mass: Moles of Zn = 1.92 g / 65.38 g/mol = 0.0294 mol.

According to the balanced equation, 1 mole of Zn produces 1 mole of H2 gas. Therefore, 0.0294 mol of Zn will produce 0.0294 mol of H2. At STP (standard temperature and pressure), 1 mol of any gas occupies 22.4 liters. Thus, the volume of H2 produced is: Volume of H2 = 0.0294 mol × 22.4 L/mol = 0.658 L of hydrogen gas.