When the temperature of a hollow sphere with 685 L (volume) of helium gas is held at 621 K (temp), the pressure of the gas is 1890 kPa. How many moles of the helium does the sphere contain?

250.88moles

Explanation:

From the question given, the following data were obtained:

V = 685 L

T = 621 K

P = 1890 kPa = 1890000Pa

Recall 101325Pa = 1atm

1890000Pa = 1890000/101325 = 18.65atm

R = 0.082atm. L/mol / K

n = ?

PV = nRT

n = PV / RT

n = (18.65 x 685) / (0.082x621)

n = 250.88moles