when the molar mass M = mass (g)/ no.of moles (Mol)
∴ moles= 0.271 g / M
By using the gas equation:
PV = n RT
when P is the pressure = 847 mmHg / 760 = 1.11 atm
V is the volume = 0.294 L
n = 0.271 / M
R is constant = 0.0821
T= 140+273 = 413 K
so by substitution:
when n = PV/RT
∴ 0.271/ M = 1.11 atm *0.294 L/ 0.0821 *413
∴ M = 28
when the empirical formula of CH2 = 12+2 = 14
∴ the exact no.of moles = 28/14 = 2
∴the molecular formula = 2(CH2) = C2H4
