calculating volume in chemistry

Question

Calculate the volume, in liters, occupied by  .990 mol of oxygen gas at STP.

Answer 1

When conditions are at STP, you don't even need to use the ideal gas law. Just remember that @ STP

1 mole of an ideal gas = 22.4 lliters.

0.990 mols x 22.4 L / mole = 22.2 L

Answer 2

You will use the ideal gas law PV = nRT

with the understanding of what STP is (standard temperature(273K) and pressure(1atm))

And use the correct value of R based on what the units for pressure are (atm)

P = 1 atm

V = x

n = 0.990mol

R = 0.0821 atm L/mol K

T = 273K

Plug values into the equation and solve for x