Answer to Question #156538 in General Chemistry for ash

Question

1. Theoretically, once can obtain zinc from an ore containing zinc sulfide, ZnS, by the reaction:

ZnS (s) 🡪 Zn (s) + S (s)

1. Show by calculation that this reaction is not feasible at 25°C.
2. Show that by compiling the above reaction with the reaction

S (s) + O2 (g) 🡪 SO2

Answer 1

For a reaction to be feasible at a given temperature, it must happen spontaneously, which means no extra energy needs to be put in for the reaction to occur. To find out whether a reaction is feasible, you can calculate the Gibbs free energy change (ΔG) for that particular reaction. ΔG = ΔH - TΔSΔH is the enthalpy change for the reaction, T is the temperature at which the reaction is occurring, and ΔS is the entropy change associated with the reaction. You can find this by subtracting the sum of the standard entropies of the reactants from the sum of the standard entropies of the products, all of which can be found in a data book. A reaction only occurs spontaneously if the Gibbs free energy change is less than zero (ie ΔG is negative).