One indicates an exothermic reaction. Phase Transitions: Enthalpy changes are associated with phase transitions like melting, vaporization, and sublimation. The change in Enthalpy can be shown as ...

If we look at this from the perspective of a gas boiler, a quick exothermic reaction, combustion, occurs. The energy is then released into the surroundings. The change in enthalpy (ΔH) is negative ...

Hess’s Law states that the enthalpy change for a chemical reaction is independent of the route taken. This means that the enthalpy change for the overall process will be identical regardless of ...

We can use these bond enthalpies to approximately calculate the enthalpy change for a given reaction.