A 100 L steel tank contains 32 kg of oxygen, O₂. If the temperature is 25ºC, what is the approximate pressure inside the tank? Choose one answer.

a. 25000 kPa

b. 800 kPa

c. 2100 kPa

d. 2.1 kPa

e. 25 kPa

 

The correct answer is MEANT to be 25000 kPa.

 

P = nRT/V
n = 32000/16 = 2000
T = 298 K
R = 8.314
V = 100L = .100 m3

P = 2000 x 8.314 x 298 / .1
  = 4955144/.1
  =49551440 Pa or 49551.440 kPa

 

Which just seems completely wrong. The only thing i wasnt sure about was the value i entered for volume, so i tried this:

 

V = nRT/P
V = 2000 x 8.314 x 298/2.5 x 10^-7 pa
  = 4955144/2.5 x 10^-7
  = 1.98 x 10^13

 

This was way off though.

 

So now i have absolutely no idea.

 

Can someone please help?

 

Thanks!

Edited June 3, 201114 yr by Triston

... the approximate pressure ...

 

I notice that your first answer is "exactly" twice the expected answer. Could the difference between atomic oxygen and molecular oxygen (O/O2) be an overlooked point in calculating your "n" value?

~

I think that you should listen to this post:

 

I notice that your first answer is "exactly" twice the expected answer. Could the difference between atomic oxygen and molecular oxygen (O/O2) be an overlooked point in calculating your "n" value?

~

 

32000/M(32 for O2)

 

Thanks for the help!