Calculate density of Oxygen at STP

[EroAlchemist]

Homework Statement

Calculate the density of Oxygen at STP using the ideal gas law

Homework Equations

PV=nRT

The Attempt at a Solution

n = (X grams Oxygen / 16g/mol Oxygen)
I set V = to 1 m3
P = 1 atm
R = 8.315 J/Mol K
T = 273 K

PV = nRT
PV/RT = n
1/(8.315*273) = X grams Oxygen / 16g/mol Oxygen
[1/(8.315*273)]*16 = X grams Oxygen
X = .007g/m3

Book answer is 1.43 kg/m3. I'm way off somewhere.
Thanks for any help!

 

[madmike159]

The SI unit of pressure is the pascal. 1 atm = 101,325 Pa. Try this in the equation and see what you get.
However I'm not sure about the *16 you got, you might want to look that up it doesn't seem right, but I can't remember how you work it out.

 

[ehild]

n = (X grams Oxygen / 16g/mol Oxygen)

Oxygen gas consist of O₂molecules. The atomic weight of the oxygen atom is 16 g/mol. The molar weight of the oxygen gas is 32 g/mol.

ehild

 

[Borek]

As madmike already signaled - watch your units. There are plenty of possible R values to select for to fit units used for volume and pressure, the one you used requires you to use pressure in Pa.

Check out table in http://en.wikipedia.org/wiki/Ideal_gas_constant