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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.