What enthalpy change means
What enthalpy change means

Chemical reactions involve breaking bonds and making bonds. Breaking bonds needs energy, making bonds releases energy, and the balance between them gives the enthalpy change, ΔH\Delta HΔH, at constant pressure, usually in kJ mol−1\text{kJ mol}^{-1}kJ mol−1.
Step-by-step lessons covering Edexcel AS Level Chemistry Enthalpy changes for AS Level Chemistry. Each lesson works through exam-style questions.