How many moles of helium are contained in a 5.00-L canister at 101 kPa and 30.0 degrees Celsius? I don't understand how to get the answer. My teacher didn't explain the work she just gave me the answer.

Answer 1

Use PV = nRT
P must be in atmospheres. 101 kPa = 1 atom (almost 1.00, technically it is 101/101.326 = ??. I don't know what your teacher recommended.)
V = 5.00 L
R = 0.08206 L*atm/mol*K
T = 30.0 C which must be converted to Kelvin.
K = 273 + 30 = ??
Substitute these values into PV = nRT an solve for n.
Using 101.325 kPa = 1 atm I obtained an answer of 0.200 moles.

Answer 2

0.200