Question

A sample of chloroethane, C2H5Cl, absorbs 0.185 kJ and begins to vaporize at its normal boiling point of 12.3°
c. What is the mass of the chloroethane sample? The molar heat of vaporization for chloroethane is 24.7kJ/mol. Enter your answer in the space provided. Round your answer to the nearest hundredths. *

Answer 1

Heat absorbed (q) = 0.185 kJ
Molar heat of vaporization (ΔH) = 24.7 kJ/ mole
molar mass of chloroethane = 64.51 g/mole
q = (ΔH) (n) where n is number of moles
n = $\frac{q}{ΔH}$
   = [tex] \frac{0.185}{24.7} = 7.5 x 10⁻³ mole
number of moles = mass (g) / molar mass
mass (g) = number of moles x molar mass
               = (7.5 x 10⁻³) x (64.51) = 0.48 g