When HCl(g) reacts with NH3(g) to form NH4Cl(s), 42.1 kcal of energy are evolved for each mole of HCl(g) that reacts. Write a balanced equation for the reaction with an energy term in kcal as part of the equation.

The chemical equation is

Explanation:

There are 2 types of reactions that are classified based on enthalpy change:

Endothermic reactions: They are defined as the reactions where heat is absorbed by the reaction. The change in enthalpy of the reaction is always positive.

Exothermic reactions: They are defined as the reactions where heat is released by the reaction. The change in enthalpy of the reaction is always negative.

Given values:

Energy released for 1 mole of HCl reacted = -42.1 kCal

The chemical equation for the formation of ammonium chloride follows: