Answer to Question #275109 in Atomic and Nuclear Physics for Jeni

Question

Calculate the molar mass of a liquid if 0.995g if it’s vapour occupy 250L at 200 degree cent and 45.0Torr

Answer 1

$m=0.995 \; g \\ V = 250 \;L \\ T = 200 = 473 \; K \\ p=45.0 \;Torr = 0.0592 \; atm$

Ideal Gas Law

pV =nRT

R = 0.08206 L×atm/mol×K

$n = \frac{pV}{RT} \\ n = \frac{0.0592 \times 250}{0.08206 \times 473} = 0.381 \; mol \\ M = \frac{m}{n} \\ M = \frac{0.995}{0.381} = 2.61 \; g/mol$