Lets assume the gas is acting Ideally, then According to Ideal Gas Equation the density is given as,
d = P M / R T ------- (1)
Where;
P = 1 atm
M = 70.90 g/mol
R = 0.08206 atm.L.mol⁻¹.K⁻¹
T = 22 °C + 273.15 = 295.15 K
Putting Values in eq. 1,
d = (1 atm × 70.90 g/mol) ÷ (0.08206 atm.L.mol⁻¹.K⁻¹ × 295.15 K)
density = 2.92 g/L