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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Win,odd Dhamnekar on July 04, 2021, 11:25:03 AM

Title: Enthalpy computation
Post by: Win,odd Dhamnekar on July 04, 2021, 11:25:03 AM
Before the introduction of chlorofluorocarbons, sulfur dioxide (enthalpy of vaporization, 6.00 kcal/mol) was used in household refrigerators. What mass of SO2  must be evaporated to remove as much heat as evaporation of 1.00 kg of CCl2F2 (enthalpy of vaporization is 17.4 kJ/mol)? The vaporization reactions for SO2 and CCl2F2 are SO2(l) :rarrow: SO2(g) and CCl2F2(l) :rarrow: CCl2F2(g) respectively.

 My answer: Molar mass of CCl2F2=120.9135 g
 So, 1.00 kg of CCl2F2=[itex]\frac{1000g}{120.9135 g}=8.27[/itex] moles
ΔH°vap of CCl2F2=17.4 kJ/mol

So, for 8.27 moles of CCl2F2, total ΔH°vap is 17.4 kJ × 8.27 moles= 143.9 kJ

Molar mass of SO2 =64.0638 g,
ΔH°vap of SO2 is  25.1208 kJ/mol

[itex] \frac{143.9 kJ}{25.1208 kJ}[/itex]= 5.73 moles of SO2

5.73 moles × 64.0638 g = 367  g   of SO2 must be evaporated.

Is this answer correct?
Title: Re: Enthalpy computation
Post by: Orcio_87 on July 04, 2021, 02:25:35 PM
Answer is correct.