Chemistry: Advanced Level

To understand chemical spontaneity, one must first address the concept of enthalpy ($\Delta H$). Historically, chemists believed that all spontaneous reactions were exothermic ($\Delta H < 0$). This alignies with the intuitive " downhill" principle—systems naturally lower their potential energy, much like a ball rolling down a hill. While this holds true for many reactions, such as the combustion of hydrocarbons, it fails to explain endothermic processes that occur spontaneously, such as the melting of ice at room temperature or the dissolving of ammonium nitrate in water. These reactions absorb heat from the surroundings, yet they proceed without external intervention. This anomaly suggests that the minimisation of energy is not the sole criterion for spontaneity.

This branch applies physics principles to chemical systems to understand the "why" and "how" behind reactions. Key topics include: chemistry advanced level

Studying large molecules and the chemical processes within living organisms, including DNA and proteins. YouTube·Richard Huish College A Level Chemistry Course Overview To understand chemical spontaneity, one must first address