Free interactive chemistry · SIM-THERMO-002
Hess’s law / Born–Haber cycle
Hess’s law and the Born–Haber cycle: the total enthalpy change does not depend on the route.
Open the interactive simulation →How to use this simulation
- In “Hess’s law”, choose a reaction and see ΔrH from formation enthalpies.
- Switch to “Born–Haber” and choose a salt (NaCl or MgO).
- Press “Next step” to add each step of the cycle.
- Read the lattice enthalpy calculated when the cycle closes.
What to notice
- Red arrows need energy; blue arrows release it.
- MgO’s lattice enthalpy is about five times NaCl’s (2+ and 2− ions).
Try this
Which single step in the NaCl cycle releases the most energy?
Try it for free →