1. 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?
Hint: Consider whether a reaction takes place in aqueous solution or instead involves noxious
gases.
Heat of reaction
Reaction
AH=-34.64 kJ/mol
NH3(9) NH3(aq)
AH=-51.6 kJ/mol
AH=-75.14 kJ/mol
NH3(aq) + HCl(aq) → NH4+(aq) + Cl(aq)
HCI(9) - HCl(aq)
AH= +14.8 kJ/mol
NH4Cl(s) - NH4+ (aq) + Cl(aq)