Question

Solve for the molar mass of a gas (M) given the following information – you must show all work, including necessary unit conversions:

a. Volume = 145.5 mL

b. Pressure = 96.58 kPa

c. Temperature = 98.7 °C

d. Mass of condensate (m) = 0.155 grams

Answer 1

we have:

P= 96.58 kPa

= (96.58*1000) pa

= 96580 Pa

= 96580.0 Pa

= (96580.0/101325) atm

= 0.9532 atm

V = 145.5 mL

= (145.5/1000) L

= 0.1455 L

T = 98.7 oC

= (98.7+273) K

= 371.7 K

find number of moles using:

P * V = n*R*T

0.9532 atm * 0.1455 L = n * 0.0821 atm.L/mol.K * 371.7 K

n = 4.545*10^-3 mol

mass of solute = 0.155 g

we have below equation to be used:

number of mol = mass / molar mass

4.545*10^-3 mol = (0.155 g)/molar mass

molar mass = 34.11 g/mol

Answer: molar mass = 34.1 g/mol