Question

Before the introduction of chlorofluorocarbons, sulfur dioxide (enthalpy of vaporization, 5.96 kcal/mol) was used in household refrigerators. What mass (in kg) of SO2 must be evaporated to remove as much heat as evaporation of 1.24 kg of CCl2F2 (enthalpy of vaporization is 20.1 kJ/mol)?

Answer 1

0.5286 kilogram of sulfur dioxide must be evaporated .

Step-by-step explanation:

Enthalpy of vaporization of chlorofluorocarbons
`H_(vap)`= 20.1 kJ/mol

Mass of chlorofluorocarbons = 1.24 kg = 1240 g

Moles of chlorofluorocarbons =
`(1240 g)/(121 g/mol)=10.2479 mol`

Heat removes by 10.2479 moles of chlorofluorocarbons : q

`q = H_(vap)* moles`

`q=20.1 kJ/mol * 10.2479 mol=205.983 kJ`

Let moles of sulfur dioxide removing 205.983 kJ(q) of heat be n.

Enthalpy of vaporization of sulfur dioxide
`H'_(vap) = 5.96 kcal/mol = 24.93664 kJ/mol`

(1 kcal = 4.184 kJ)

`q=H'_(vap)* n`

`205.983 kJ=24.93664 kJ/mol* n`

n = 8.2603 moles

Mass of 8.2603 moles of sulfur dioxide =

`8.2602 mol* 64 g/mol=528.6592 g=0.5286 kg`

0.5286 kilogram of sulfur dioxide must be evaporated .