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Chemistry - Thermodynamics - II Question with Solution | TestHub

ChemistryThermodynamics - IIFree Energy and EquilibriumMedium2 minPYQ_2017
ChemistryMediumsingle choice

The standard state Gibb's free energies of formation ofC(graphite) andC(diamond) atT=298 Kare
ΔfGoC (graphite=0 kJ mol-1
ΔfGoC diamond=2.9 kJ mol-1
The standard state means that the pressure should be 1 bar, and substance should be pure at a given temperature. The conversion of graphite [C(graphite)] to diamond [C(diamond)] reduces its volume by2×10-6 m3 mol-1. IfC(graphite) is converted toC(diamond) isothermally atT=298 K, the pressure at whichC(graphite) is in equilibrium withC(diamond), is
[Useful information:1 J=1 kg m2 s-2, 1 Pa=1 kg m-1s-2; 1bar=105Pa]

Options:

Answer:
A
Solution:

CgraphiteCdiamond; ΔGo=ΔfGdiamondo-ΔfGgraphiteo=2.9 kJ/mol  at 1 bar

As dGT=V.dP

ΔG1ΔG2dΔGT= P1P2ΔV.dP

ΔG2-ΔG1=ΔV. P2-P1

2.9×103-0=-2×10-6 1-P2

P2-1=2.9×1032×10-6Pa=1.45×104 bar

P2=14501  bar.

Stream:JEE_ADVSubject:ChemistryTopic:Thermodynamics - IISubtopic:Free Energy and Equilibrium
2mℹ️ Source: PYQ_2017

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