Given that the compound’s empirical formula is CH2, what is the molar mass of the compound?

For the vapor of the compound :
Mass, m = 0.0184 g
Volume, V = 5.58 mL = 0.00558 L
Absolute temperature, T = (273 + 45) K = 318 K
Pressure, P = 1 atm
Gas constant, R = 0.08206 L atm / (mol K)
Molar mass, M = ? g/mol

PV = nRT and n = m/M
Hence, PV = (m/M)RT
and thus M = mRT/(PV)

Molar mass, M = 0.0184 × 0.08206 × 318 / (1 × 0.00558) = 86.0 g/mol


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Additionally, let (CH₂)n be the molecular formula of the compound.

Molar mass of C = 12.0 g/mol
Molar mass of H = 1.0 g/mol

Molar mass of the compound (in g/mol) :
n (12.0 + 1.0×2) = 86.0
n ≈ 6

The molecular formula = C₆H₁₂