An unknown amount of helium (He) gas occupies 10.5 L at 1.47 atm pressure and 321 K. What is the mass of helium gas in the container?

Use R = 0.0821 L.atm/(mol.K).

____________ g He. Do NOT enter unit. Report your final answer with 3 SFs.

3 answers

Use PV = nRT and solve for n = number of mole He.
Then mol He x molar mass He = grams He. Remember to use T in kelvin.
degrees L = degrees C + 273 = ?
Post your work if you get stuck.
I am just entering the numbers in the right column so you will know where I got numbers from.
V = 10.5
P = 1.47
T = 321 K
R = 0.0821
M = 4.003g/mol
Here's the work,, Let me know if I did anything wrong.
N = P1 V1 / RT1 =
(1.47atm)(10.5) = 15.435 / (0.0821) (321) = 26.3541
15.435 / 26.3541 = 0.58567
m = n x m
= (0.58567mol) (4.003g/mol) = 2.34444
Correct answer is 2.34
Am I right @DrBob222?
Everything looks ok to me.