Question

volume = 322 mL
temperature = 150 celcius
pressure = 175 kPa
mass = 0.448
Calculate the molar mass of the gas.

First I converted volume to 0.332 L.
Second I converted 150 celcius into 423 kelvin.

PV = nRt
(175)(0.322) = n(8.314)(423)
n= 0.016022988
molar mass = 0.448/0.016022988
= 30.5 g/mol

If the gas is known to be diatomic, predict it's identity.

I divide the 30.5 by 2 to get 15.25. That number falls inbetween nitrogen and oxygen so i'm not too sure which one it would be. Apparently there is one correct answer. Im not too sure if I did the first part correctly :S

Answer 1

The first part looks ok for the method but I think you made a bobble on the calculator. I get something closer to 28 than 30. And 1/2 of about 28 would be about 14 which would be ok.

Answer 2

I did make a mistake on my calculator. Thanks a lot :)