Mole percent composition of earths dry atmosphere is 78% N2, 21% O2 and 1.00% Ar.

Question

Using the atmospheric pressure you recorded in the lab during this experiment (757.5 mmHg) and an ambient temperature of 25C, calculate partial pressures of these 3 gases.

Answer 1

PN2 = 0.78*Ptotal
PO2 = 0.21*Ptotal
PAr = 0.01*Ptotal
All partial pressures are at 25 IF the total P you measured (757.5 mm) was at 25C. If not at 25 you need to correct 757.5 mm from room T to 25 C. Use (P1V1/T1) = (P2V2/T2) for that correction.

Answer 2

What is the p total?

Answer 3

757.5 mm Hg if that's what you measured. I saw one of your other questions which Bob Pursley answered about vapor pressure of water and you quoted 757.5 mm Hg for that one too. Don't mix these two problems together. For this problem as you have quoted it here the partial pressure of N2 is 0.78*757.5 = ? mm Hg.