Calculate change in standard enthalpy

Question

Consider the chemical equations for the given reactions. Use the standard enthalpies of formation to calculate the changes in the standard enthalpies of formation to calculate the changes in the standard enthalpies of reaction.

(a) NaOH (aq) + HNO₃ (aq) ⟶ NaNO₃ (aq) + H₂O (l)

ΔH°rxn = ? kJ

(b) NaOH (aq) + NH₄NO₃ (aq) ⟶ NaNO₃ (aq) + NH₃ (aq) + H₂O (l)

ΔH°rxn = ? kJ

(c) HNO₃ (aq) + NH₃ (aq) ⟶ NH₄NO₃ (aq)

ΔH°rxn = ? kJ

Answer 1

Look up the standard enthalpies of formation of each product and reactant. To find enthalpy of each reaction, subtract the sum of the enthalpies of the products from the sum of the enthalpies of the reactants.