State Hess's law.

In the subtopic Applications of Hess's law, this AQA A-Level Chemistry 7405 learning objective focuses on state Hess's law. It belongs to Energetics, so revision should stay anchored to this exact subtopic rather than drifting into a generic GCSE-level chemistry summary. Approved keywords to use include Hess's law. Hess's law. means the total enthalpy change for a reaction is the sum of the enthalpy changes for the individual steps, regardless of the pathway taken Avoid the mistake of students often confuse Hess's law with the concept of enthalpy changes in individual reactions, thinking it only applies to direct reactions; instead, hess's law states that the total enthalpy change for a reaction is the sum of the enthalpy changes for individual steps, regardless of the pathway taken. To apply Hess's law correctly, identify the individual enthalpy changes and sum them up to find the total enthalpy change for the overall reaction For exam answers, remember that Hess's law states that the total enthalpy change for a reaction is the same, regardless of the number of steps taken to achieve the reaction