What volume of H2 gas (in liters), measured at 23 °C and 678 torr, can be obtained by reacting 7.59 g of zinc metal with 124 mL of 0.302 M HCl?

Question

Zn + 2HCl --> ZnCl2 + H2

Answer 1

This is a limiting reagent (LR) problem and you know that because amounts are given for BOTH reactants.

mols Zn = grams/atomic mass = ?
mols HCl = M x L = ?

Using the coefficients in the balanced equation, convert mols Zn from above into mols H2.
Do the same for mols HCl to mols H2.
It is likely that these two values will not be the which means one is not right; the correct value in LR problems is ALWAYS the smaller value and the reagent producing that value is the LR.

Using the smaller value for mols, use PV = nRT to solve for V in liters.