Question

Please help with these

1. Calculate ΔG (in kJ) at 298 K for some solid ZnF₂, 0.082 M Zn²⁺ and 0.039 M F^-(aq).

2.Calculate the equilibrium constant at 45 K for a reaction with ΔH_rxn^o = 10 kJ and ΔS_rxn^o = -100 J/K. (Don't round unil the end. Using the exponent enlarges any round-off error.

Calculate the equilibrium constant at 136 K for the thermodynamic data in the previous question. ( Problem 2)

Answer 1

1) ∆G = -RTlnK

K = [Zn ²⁺][F^-]² = (0.082)(0.039)² = 1.25×10^-4

T = 298K

R = 8.314×10^-3 KJ/mol.K

∆G = -8.314×10^-3×298×ln(1.25×10^-4)

= 22.27 KJ

2) ∆G = ∆H - T∆S = 10 - 45(-100/1000) KJ

= 10 + 4.5 = 14.5 KJ

K = e^{​​​​​​-(∆G/RT)} = e^{-(14.5/0.008314×45)} = 1.47×10^-17

3) ∆G = 10-136(-0.1) = 23.6 KJ

K = e^{-23.6/0.008314×136} = 8.64×10^-10