What entropy measures
What entropy measures
Entropy, SSS, measures the freedom of particles in a system and the number of ways particles and energy can be arranged. At this level, it is better to think about particle freedom than to rely on the vague word "disorder".
Step-by-step lessons on Eduqas A Level Chemistry Entropy and feasibility of reactions. Each one builds up to exam-style questions. Build confidence with atomic structure, bonding and moles calculations early on, since these underpin the more demanding organic mechanisms, equilibrium and practical-analysis topics that dominate Year 2.