Answer: OXYGEN
Explanation:
As density is given as,
d = P M / R T
Solving for M,
M = d R T / P ------ (1)
Data Given:
d = 1.25 × 10⁻⁶ g/cm³ = 0.00125 g/L
R = 0.08206 L.atm.mol⁻¹.K⁻¹
T = 40 °C + 273 = 313 K
P = 1.00 × 10⁻³ atm
Putting values in eq. 1,
M = (0.00125 g.L⁻¹ × 0.08205 atm.L.mol⁻¹.K⁻¹ × 313 K) ÷ 1.0 × 10⁻³ atm
M = 32.10 g/mol
Result:
Molecular Mass of O₂ is 32 g/mol.