Gas laws chemistry

Question

1) NH3 gas is pumped into the reservoir of a refrigeration unit at a pressure of 3.50 atm. The capacity of the reservoir is 10.4 L. The temperature is 42.7◦C. What is the mass of the gas?

2) What pressure is exerted by 0.150 mol of hydrogen gas in a 6.26 L container at 33◦C?

Answer 1

Use the ideal gas law to find the moles of NH3, and then convert that to grams:

PV = nRT

n = PV/RT = (3.50 atm)(10.4 L)/(0.0821 Latm/Kmol)(315.7K)

n = 1.40 moles NH3

mass = 1.40 moles NH3 x 17 g/mol = 23.9 g NH3

P = nRT/V = (0.150 mol)(0.0821 Latm/Kmol)(306K)/6.26 L

P = 0.602 atm