Yes, I can help you calculate the chemical exergy of a saturated mixture of water-ammonia.

The chemical exergy of a substance is defined as the maximum amount of work that can be obtained when the substance undergoes a chemical reaction with the environment and is brought to a reference state (usually standard conditions). To calculate the chemical exergy of a saturated mixture of water-ammonia, you will need to follow these steps:

1. Determine the composition of the mixture, usually expressed in terms of mass or mole fractions.

2. Determine the enthalpy and entropy of the mixture at the given conditions, using thermodynamic data such as steam tables or software.

3. Calculate the Gibbs free energy of the mixture using the following equation:

G = H - TS

where G is the Gibbs free energy, H is the enthalpy, T is the temperature, and S is the entropy.

4. Determine the reference state for the mixture, which is usually taken as the standard state of the pure components at the same temperature and pressure.

5. Calculate the chemical exergy of the mixture using the following equation:

Ex = (G - G_ref) + RT ln(P/P_ref)

where Ex is the chemical exergy, G is the Gibbs free energy of the mixture, G_ref is the Gibbs free energy of the reference state, R is the gas constant, T is the temperature, P is the pressure of the mixture, and P_ref is the reference pressure.

Note that the reference state may differ depending on the specific application or context of the calculation, so it is important to be clear about the reference state being used.

I hope this helps you in calculating the chemical exergy of a saturated mixture of water-ammonia.