Zn(s) + 2 HCl(aq) H2(g) + ZnCl2(aq)

When 25.0 g of Zn reacts, how many L of H2 gas are formed at STP?

1. 0.382 L
2. 0.0171 L
3. 22.4 L
4. 8.56 L
5. 4.28 L

3 answers

Here is a worked example. Just follow the steps. At the end you may convert moles H2 to volume by L = moles x 22.4.
http://www.jiskha.com/science/chemistry/stoichiometry.html

Number 4

4. 8.56L of H2