Explain Gibb's Helmholtz equation.

When ∆G is positive, the process is always non-spontaneous. Explain.

Prove that ∆G = –T∆S_total.

What is free energy change? Show that the change in free energy is equal to useful work done.
or
prove that –∆G = w_{(useful work)}

Predict the enthalpy change, free energy change and entropy change when ammonium chloride is dissolved in water and the solution becomes colder.

At , ice and water are in equilibrium and  for the process   Calculate  for the conversion of ice to liquid water.

For the reaction

calculate  at 700K when enthalpy and entropy changes are -113 kJ mol^-1 and -145 JK^-1 mol^-1 respectively.

From the following values of ∆H and ∆S, decide whether or not these reactions will be spontaneous at 298 K:

Reaction A:
∆H = – 10.5 X 10³ J mol^–1
∆S = + 31 JK^–1 mol^–1

Reaction B:
∆H = – 11.7 X 10³ J mol^–1 ;
∆S = –105 jK^–1 mol^–1.