Suppose you wanted to calculate the heat of reaction for the formation of ammonia gas and gaseous hydrochloric acid (both of which are potentially dangerous in gaseous form) from solid ammonium chloride. A. Write a balanced equation for this reaction.
B. The heat of reaction for the process described in (a) can be determined by applying Hess's law. The heats of reaction shown in the table below can be obtained experimentally or looked up in tables of enthalpy data. Which two of these heats of reaction would be the easiest and safest to measure in the laboratory, and which two are better obtained through reference sources? Why?
Reaction Heat of reaction
NH3(g) → NH3(aq) ΔH = -34.64 kJ/mol
NH3(aq) + HCl(aq) → NH4+(aq) + Cl-(aq) ΔH = -51.6 kJ/mol
HCl(g) → HCl(aq) ΔH = -75.14 kJ/mol
NH4Cl(s) → NH4+(aq) + Cl-(aq) ΔH = +14.8 kJ/mol
C. What is the heat of reaction for the process described in (a)?