Chemistry Homework Question?

Question

Can you please show your work

1) A sample of oxygen gas is saturated with water vapor at 27 degrees C. The total pressure of the the mixture is 772 torr and the vapor pressure of the water is 26.7 torr at 27 degrees C. What is the partial pressure of the oxygen gas?

2) A sample of Oxygen gas is collect by displacement of water at 25 degrees C and 1.02 atm total pressure. If the vapor pressure of water is 23.756 mm Hg at 25 degrees C, what is the partial pressure of the oxygen gas in the sample.

3) A 500. mL sample of O2 gas at 24 degrees C was prepared by decomposing a 3% aqueous solution of hydrogen peroxide , H2O2, in the presence of a small amount of manganese catalyst. The oxygen thus prepared was collected by displacement of water. The total pressure of gas collected was 755 mm Hg. What is the partial pressure of O2 in the mixture? (The vapor pressure of water at 24 degrees C is 23 mm Hg.)

Answer 1

The answer is 0.  Just write 0 for all the questions.

Answer 2

no idea on 3 for 2 convert mm hg to atm and for 1 i think the answer is 713.9777777777 not sure how many sig figs u need