contestada

A sample containing 3.25 moles of He is mixed with 2.25 moles of Ne and 1.75 moles of Ar.All components are at 1 bar and 350 K. Calculate ∆mixG.

Respuesta :

Answer : The value of [tex]\Delta G_{mix}[/tex] is, -22.5 kJ

Explanation :

The formula used for [tex]\Delta G_{mix}[/tex] is:

[tex]\Delta G_{mix}=nRT\times [X_{He}\ln (X_{He})+X_{Ne}\ln (X_{Ne})+X_{Ar}\ln (X_{Ar})][/tex]

where,

n = number of moles = 3.25 +2.25 + 1.75 = 7.25 moles

R = gas constant = 8.314 J/mole.K

T = temperature = 350 K

X = mole fraction

First we have to calculate the mole fraction of He, Ne and Ar.

[tex]\text{Mole fraction of }He=\frac{\text{Moles of }He}{\text{Moles of }He+\text{Moles of }Ne+\text{Moles of }Ar}=\frac{3.25}{3.25+2.25+1.75}=0.448[/tex]

and,

[tex]\text{Mole fraction of }Ne=\frac{\text{Moles of }Ne}{\text{Moles of }He+\text{Moles of }Ne+\text{Moles of }Ar}=\frac{2.25}{3.25+2.25+1.75}=0.310[/tex]

and,

[tex]\text{Mole fraction of }Ar=\frac{\text{Moles of }Ar}{\text{Moles of }He+\text{Moles of }Ne+\text{Moles of }Ar}=\frac{1.75}{3.25+2.25+1.75}=0.241[/tex]

Now we have to calculate the value of [tex]\Delta G_{mix}[/tex].

[tex]\Delta G_{mix}=nRT\times [X_{He}\ln (X_{He})+X_{Ne}\ln (X_{Ne})+X_{Ar}\ln (X_{Ar})][/tex]

[tex]\Delta G_{mix}=(7.25mol)\times (8.314J/mol.K)\times (350K)\times [0.448\ln (0.448)+0.310\ln (0.310)+0.241\ln (0.241)][/tex]

[tex]\Delta G_{mix}=-22483.4J=-22.5kJ[/tex]

Thus, the value of [tex]\Delta G_{mix}[/tex] is, -22.5 kJ