Hydrogen gas is produced when zinc reacts with sulfuric acid:

Question

Zn(s)+H_2SO_4(aq)---ZnSO_4(aq)+H_2(g)

If 160 mL of wet H_2 is collected over water at 24 Celsius and a barometric pressure of 739 torr, how many grams of Zn have been consumed? (The vapor pressure of water is 22.38 torr.)

Answer 1

Use PV = nRT to solve for n = number of moles H2, then use stoichiometry (link supplied for a worked example) to calculate grams Zn used.
http://www.jiskha.com/science/chemistry/stoichiometry.html