Magnesium is a valuable, light weight metal used as a structural material as well as in alloys, batt — Metallurgy and Isolation of Elements Chemistry Question
Question
Magnesium is a valuable, light weight metal used as a structural material as well as in alloys, batteries, and in chemical synthesis. Although magnesium is plentiful in Earth's crust, it is mainly found in the sea water (after sodium). There is about 1.3 g of magnesium in every kilogram of sea water. The process for obtaining magnesium from sea water employs all three types of reactions, i.e., precipitation, acid-base, and redox-reactions.
💡 Solution & Explanation
Step 1: Write down the net reaction for the reduction of ZnO by Carbon: ZnO(s) + C(s) -> Zn(s) + CO(g). Step 2: Calculate the standard Gibbs free energy change (ΔG°_reaction) for this net reaction: ΔG°_reaction = ΔG°_f(CO) - ΔG°_f(ZnO) = -460 kJ/mol - (-360 kJ/mol) = -100 kJ/mol. Step 3: Since the net Gibbs free energy change is negative (-100 kJ/mol), the reduction of ZnO by Carbon is thermodynamically spontaneous at 1000°C, meaning ZnO can be reduced to Zn by C (option b).