HOW DO I SOLVE this question

Question

How many moles of gas are in a breath of 20.1 L at a temperature of 21.3 C and a pressure of 1.2 atm?

Answer 1

Ideal gas law: PV = nRT

P = pressure = 1.2 atm

V = volume = 20.1 L

n = moles = ?

R = gas constant = 0.0821 Latm/Kmol

T = temp in K = 21.3 + 273 = 294.3K

Solving for n, we have..

n = PV/RT = (1.2)(20.1) / (0.0821)(294.3)

n = 0.998 moles (to 3 sig. figs.)