Question

1. Since the gas in your graduated cylinder is a mixture of butane and water vapor, you must determine the partial pressure of the butane, Pbutane, alone. To do this, consult a reference and record the partial pressure of the water vapor, Pwater, at the temperature you recorded. Use the following formula to compute the partial pressure of the butane.

Answer 1

get the listed partial pressure of water vapor at your temperature, for a chart.

Pressurebutant=totalpressue-PartialPressureH2O

Answer 2

I don't see a formula but it is this.
Ptotal = pbutane + pH2O

Look in your text for a table of vapor pressures for water or look on google to that and record that as pH2O. The total pressure will be the atmospheric pressure at the time you did the experiment. Substitute and calculate pbutane.