# Ideal Gas Law (Simple )

1. Sep 9, 2007

### Rockstar47

1. The problem statement, all variables and given/known data

I need to find the volume for 1 kg of diatomic oxygen for a pressure of 150,000 Pa and a temperature of 100K. This is really part of a larger project, and I need to make sure I'm not tripping up on little details. It's that 1 kg of diatomic oxygen that I am a bit unsure about, or just plain having a brain freeze about.

R* = 8.314 J/K*mol
T = 100 K
P = 150,000 Pa
n = ??

2. Relevant equations

PV = nRT

3. The attempt at a solution

Solving the equation for V; V = nRT/P. No big deal. My problem is making sure I have the correct n in the equation. The mass of diatomic oxygen is 32.0 grams, which is what I was using in my solutions. However, I realize that I have 1 kg of O2, not 1 g of it. Should I really be using 32,000 for my n? Or something else?

2. Sep 9, 2007

### rocomath

you're using the wrong R constant. i'm working on it right now.

Last edited: Sep 9, 2007
3. Sep 9, 2007

### hage567

You haven't properly converted mass to moles. Check that your units make sense in your calculation.

4. Sep 9, 2007

5. Sep 9, 2007

### Rockstar47

Thanks, everyone.

If I am looking at this all correctly, since I have 1 kg of diatomic oxygen, my number of moles should be: 1000 g / 32.00 g, which gives me my number of moles (n) equal to 31.25. Am I on the right track now?

6. Sep 9, 2007

yeppp

7. Sep 9, 2007

### Rockstar47

Thanks for the help, everyone!! It was a total brain freeze on my part...

8. Sep 9, 2007