Calculate the volume of hydrogen produced by the electrolysis of 54.0 mL of water at 27.°C and 1.3 atm, using the ideal gas approximation.
2H2O ==> 2H2 + O2
54.0 mL H2O = 54.0 grams.
Convert 54.0 grams H2O to moles. moles = grams/molar mass
Using the coefficients in the balanced equation, convert moles H2O to moles H2.
Now use PV = nRT to convert moles H2 to volume H2 at the conditions listed. Remember T must be in kelvin.