Question

What is the density of O₂ at 27°C with pressure 1 atm? 

(a) 1.1 g/l 

(b) 1.3 g/L 

(c) 1.5 g/L 

(d) 1.7 g/L

Answer 1

(b) 1.3 g/L 

T = 27 + 273 = 300 k

Molecular weight of O₂ = 16 x 2 = 32g

for ideal gas, pV = nRT

⇒ pV = m/M RT

⇒ d = PM/RT = 32 x 1 / 0.0821 x 300 = 1.3 g/L