Problem: What is the enthalpy change for the reaction MgO(s) + 2 HCl(g) → MgCl2(s) + H2O(l) ? The enthalpies for formation are -601.7 kJ/mol for MgO, -92.3 kJ/mol for HCl, -641.6 kJ/mol for MgCl2, and -285.8 kJ/mol for H2O.

FREE Expert Solution

We’re being asked to determine the standard enthalpy change (ΔH˚rxn) for the balanced reaction:

MgO(s) + 2 HCl(g) → MgCl2(s) + H2O(l)


Recall that ΔH˚rxn can be calculated from the enthalpy of formation (ΔH˚f) of the reactants and products involved:

ΔH°rxn=ΔH°f, prod-ΔH°f, react


The ΔH˚f values given:


83% (340 ratings)
View Complete Written Solution
Problem Details

What is the enthalpy change for the reaction MgO(s) + 2 HCl(g) → MgCl2(s) + H2O(l) ? 

The enthalpies for formation are -601.7 kJ/mol for MgO, -92.3 kJ/mol for HCl, -641.6 kJ/mol for MgCl2, and -285.8 kJ/mol for H2O.

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Enthalpy of Formation concept. You can view video lessons to learn Enthalpy of Formation. Or if you need more Enthalpy of Formation practice, you can also practice Enthalpy of Formation practice problems.