Write balanced chemical equations for the following reactions. (a) The reaction of aluminum and iron(III) oxide to form iron and aluminum oxide (known as the thermite reaction). (b) The reaction of carbon and water at high temperature to form a mixture of gaseous CO and H2 (known as water gas and once used as a fuel). (c) The reaction of liquid silicon tetrachloride and magnesium forming silicon and magnesium chloride. This is one step in the preparation of ultrapure silicon used in the semiconductor industry

The carbon dioxide exhaled in the breath of astronauts is often removed from the spacecraft by reaction with lithium hydroxide 2LiOH(s)+CO2(g)Li2CO3(s)+H2O(l) Estimate the grams of lithium hydroxide required per astronaut per day. Assume that each astronaut requires 2.50 103 kcal of energy per day. Further assume that this energy can be equated to the heat of combustion of a quantity of glucose, C6H12O6, to CO2(g) and H2O(l). From the amount of glucose required to give 2.50 103 kcal of heat, calculate the amount of CO2 produced and hence the amount of LiOH required. The H for glucose(s) is 1273 kJ/mol.

Three reactions very important to the semiconductor industry are The reduction of silicon dioxide to crude silicon, SiO2(s) + 2 C(s) → Si(s) + 2 CO(g) ΔrH° = 689.9 kJ/mol The formation of silicon tetrachloride from crude silicon, Si(s) + 2 Cl2(g) → SiCl4(g) ΔrH° = −657.01 kJ/mol The reduction of silicon tetrachloride to pure silicon with magnesium, SiCl4(g) + 2 Mg(s) → 2 MgCl2(s) + Si(s) ΔrH° = −625.6 kJ/mol Calculate the overall enthalpy change when 1.00 mol sand, SiO2, changes into very pure silicon by this series of reactions.