Given the reaction, H2 + Cl2 → 2HCl, if 12.0 moles of HCl were made, then how many moles of H2 were used?a.24.0 moles b.12.0 moles c.6.00 moles d.3.00 moles

Chemistry · Middle School · Sun Jan 24 2021

Answered on

To determine how many moles of H2 were used, we need to look at the stoichiometry of the balanced chemical equation. The balanced equation is:

H2 + Cl2 → 2HCl

This equation tells us that 1 mole of H2 reacts with 1 mole of Cl2 to produce 2 moles of HCl. Thus, the molar ratio of H2 to HCl is 1:2.

If 12.0 moles of HCl were produced, we use the ratio to find the moles of H2 that reacted:

1 mole H2 / 2 moles HCl = x moles H2 / 12.0 moles HCl

Cross-multiplying to solve for x:

x moles H2 * 2 moles HCl = 1 mole H2 * 12.0 moles HCl x moles H2 = 12.0 moles HCl / 2 x moles H2 = 6.00 moles

Therefore, 6.00 moles of H2 were used.

The correct answer is c.6.00 moles.