Question

When 14.0 g of zinc metal reacts with excess hcl, how many litres of h2 gas are produced at stp? zn(s) + 2hcl(aq) → zncl2(aq) + h2(g)

Answer 1

Convert the given mass of Zn to moles:

(14.0 g) (1/65.32 mol/g) ≈ 0.214 mol Zn

According to the balanced reaction, 1 mol H₂ gas is produced for every 1 mol Zn consumed in the reaction, so get the same number of moles of H₂.

Convert this amount of H₂ to a volume at STP:

(0.214 mol H₂) (22.4 L/mol) ≈ 4.80 L H₂