A sample of helium has a volume of 150.0 L at STP. How many moles of helium are in the container?

The answer to your question is n = 6.24 moles

Explanation:

Data

Volume = 150 l

moles = ?

Temperature = 20°C

Pressure = 1 atm

R = 0.082 atm L / mol°K

Process

1. - Convert temperature to °K

T = 20 + 273 = 293°K

2. - Use the formula of ideal gases

Formula

PV = nRT

-Solve for n

n = PV/RT

-Substitution

n = (1) (150) / (0.082) (293)

-Simplification

n = 150 / 24.026

-Result

n = 6.24 moles