Question

9. Consider the ribonuclease folding reaction,

U → F

Experimental measurements indicate the following thermodynamic parameters (T=298K):

ΔGo' (kJ/mol)	ΔHo' (kJ/mol)	ΔSo' (J/K∙mol)
-46	-280	-790

Calculate the equilibrium constants at T=298K and T=310K.



K_{298 = ________}



K310 = ________

Answer 1

a)
At 298 K
deltaGo = -46 KJ/mol
deltaGO = -46000 J/mol

we have below equation to be used:
deltaGO = -R*T*ln Kc
-46000 = - 8.314*298.0* ln(Kc)
ln Kc = 18.5666
Kc = 1.157*10^8
Answer: 1.16*10^8

b)
Now we have:
deltaHo = -280.0 KJ/mol
deltaSo = -790 J/mol.K
= -0.79 KJ/mol.K
T = 310 K

we have below equation to be used:
deltaGo = deltaHo - T*deltaSo
deltaGo = -280.0 - 310.0 * -0.79
deltaGo = -35.1 KJ/mol
So, at 310 K
deltaGo = -35.1 KJ/mol
deltaGo = -35100 J/mol

we have below equation to be used:
deltaGo = -R*T*ln Kc
-35100 = - 8.314*310.0* ln(Kc)
ln Kc = 13.6187
Kc = 8.213*10^5
Answer: 8.21*10^5