Question

I need help on this chemistry work. Thanks.

DATA ANALYSIS

Using the example, calculate the Gibbs free energy for the process of dissolving ammonium nitrate and the process of dissolving sodium hydroxide (equation: ΔG = ΔH – TΔS).

Use the standard temperature 298 K.

Use the experimental data to calculate enthalpy of dissolving (ΔH).

Use the following data to calculate the entropy change (ΔS):

	S (J/K mol)
NH4NO3(s)	151
NH4+(aq)	113.4
NO3-(aq)	146.4
NaOH(s)	64.46
Na+(aq)	59.0
OH-(aq)	- 10.7

After completing the calculations answer the following questions separately for each experiment:

Is the dissolving exothermic or endothermic?

Does the entropy decreases or increases during dissolving?

Is the Gibbs free energy positive or negative? Is the process of dissolving spontaneous?

Using data in the appendix in your textbook, calculate Gibbs free energy for the reaction of dissolving

lithium phosphate, Li₃PO₄, in water at 25 °C. Do the calculations in two ways:

1) Use standard enthalpy of formation (ΔH) and entropy (S) from the appendix in your textbook, and use the same formula as you did in the lab experiments: ΔG = ΔH – TΔS. Remember that both ΔH and ΔS has to include three lithium ions.

2) Use standard free energies of formation from Appendix 6 (ΔG) and equation

ΔG = ∑ΔG _products – ∑ΔG _reactants

Are the results similar in both calculations?