Gas Laws Chemistry Question

Question

how to find the number of miles of hydrogen gas collected when you are told...that the volume is 90.0 mL, the temperature is 25 degrees Celsius, the atmospheric pressure is 745 mm Hg, and that the equilibrium vapor pressure of h20 is 23.8 mm Hg? 

Answer 1

Subtract the vapor pressure of water from the atmospheric pressure. This will give you the partial pressure of hydrogen gas. Then, use the ideal gas law to find out the number of moles of hydrogen gas the calculated partial pressure corresponds to.