Question

1. What does AH signify, and what is the difference between a reaction whose AH is positive and one whose AH is negative? (2 pts)

Answer 1

∆H signifies the enthalpy of a reaction

Or we can say that it is the enthalpy change of a reaction when reactants convert into product.

∆H (reaction) = ∆H (product) - ∆H (reactants)

If ∆H is positive it indicates that the reaction is endothermic or heat is required for the conversion of reactant into product.example conversion of ice into vapours is endothermic reaction

If ∆H is negative then the reaction is exothermic ,and the heat is evolved during the conversion of reactant into product . example burning of candle , respiration, reaction of acid with water etc.