Calculating Volume for 1 kg of O2 at 150,000 Pa and 100K using Ideal Gas Law

[Rockstar47]

Homework Statement

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 = ??

Homework Equations

PV = nRT

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?

 

[rocomath]

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

 

[hage567]

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

 

[Astronuc]

The significance of diatomic is that one uses 32 g/g-mole. The basis of 1 mole is Avogadro's number of atoms (or molecules) in a gram mole, where the value for grams = atomic (or molecular) mass.

At STP, 1 mole of ideal gas has a volume of 22.4 l.

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html#c4

but review the entire page
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html

 

[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?

 

[rocomath]

yeppp

 

[Rockstar47]

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

 

[rocomath]

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

what was your final answer?