# Ideal gas law and pressure

1. Jun 3, 2005

### sghaussi

hello all. I'm trying to figure out this problem and it's bugging me because it's soooo simple yet i keep getting the wrong answer. here's the problem:

If 1.00 mol of carbon dioxide gas at 350 K is confined to a volume of 400 cubic centimeters, find the pressure of the gas using the ideal-gas equation.

Okay.. I know that the ideal gas equation will look like this if I am solving for pressure:

p = (nRT)/V

since I want pressure in pascals, then I will convert volume V to cubic meters, and for R constant I will use R = 8.3145 J/mol K

so far this is the information I have:

R = 8.3145 J/mol K
T = 350 K
n = 1.00 mol
V = 4 cubic meters

When I try and solve for pressure, I get 727.5 pascals. I did this 5 times, and I keet getting the same answer. however the book is telling me I'm wrong. Am I not understanding this correct? could this be one of those times the book is wrong? I hope someone can help!

2. Jun 3, 2005

### Peter.E

Your conversion into cubic metres is incorrect, remember it is cubic:

Therefore;

0.0004m^3

Use that value for volume and you should calculate the correct answer, which is 7275187Pa or 7.3MPa.

Last edited: Jun 3, 2005
3. Jun 3, 2005

### yessien

V = 400 cm^3 = 400 * (10^-2 m)^3 = 400 * 10^-6 m^3 = 0.0004 m^3
I think this is correct value of the volume and if you put it into ideal gas equation you'll get the right answer (i think).

4. Jun 3, 2005

### sghaussi

thanks to the both of you for your help. i was able to figure it out.. silly mistake. =) night!