Chemistry stoich question.

[Howard]

In a mixture of nitrogen and oxygen gas, there is 1.4 mol of nitrogen. If the nitrogen has a partial pressure of 40.8 kPa and the total pressure of the gas is 102.8kPa, how many moles of oxygen are present?

I ended up with 0.844 mol of oxygen. But it's wrong. Any ideas?

 

[Howard]

Nm, I think I got it.

 

[Cycad]

3.52

 

[GoSharks]

p1/pt = m1/mt
40.8/102.8 = 1.4/x

3.52 is the # of total mols.

#moles 02 = 3.52 - 1.4 = 2.1

 

[Pastore]

42

 

[snik]

Originally posted by: GOSHARKS
p1/pt = m1/mt
40.8/102.8 = 1.4/x

3.52 is the # of total mols.

#moles 02 = 3.52 - 1.4 = 2.1

That what I got too.

 

[MikeMike]

DAH this stuff is gunna be on my final, i need to study!

 

[Howard]

I did this, which seems to be simpler than the above methods.

n1/p1 = n2/p2

1.4/40.8 = n2/62
n2 = 1.4(62)/40.8
n2 = 2.12mol