The document is a GCSE (9–1) Combined Science (Chemistry) A past paper, focusing on key chemistry topics. It covers reaction types (displacement, thermal decomposition, cracking), properties of hydrocarbons, the reactivity series, and environmental chemistry (atmospheric changes, water purification). It examines practical chemistry through questions on experimental setups, catalyst identification, and reaction rate analysis. Other areas include trends in Group 7 elements, energy transfer in reactions, and industrial processes like fractional distillation and water treatment. The paper tests applied knowledge, data interpretation, and scientific reasoning through various question types and practical contexts.