[xeomonk]

Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules. Several other gases make up the remaining 1% of air molecules.

What is the partial pressure of nitrogen in air at atmospheric pressure (1 atm)? Assume ideal behavior.

I know that the number of molecules of a gas is directly related to the number of moles of that gas. Thats basically what I know. What would be the first step I need to solve this problem?

[Borek]

What is partial pressure definition?

How is number of molecules related to number of moles of substance?

[xeomonk]

The partial pressure is the pressure exerted by just one type of gas in a mixture. A partial pressure is calculated using only the number of moles of that particular gas, instead of the total number of moles:

P₁=n₁RT/V

related by the number of moles of a gas is directly related to its partial pressure because volume and temperature must be the same for all the gases in a mixutre.

right? 

[xeomonk]

I got the answers

I just need to take the percentage and divide that by 100

[Borek]

But do you understand why?