Chemical Reactions and Equations

Where this fits in the syllabus

Grade 11 · Term 1

Key points to revise

Revise Chemical Reactions and Equations fast with concise, exam-ready key points

About O/L Science: O/L Science integrates physics, chemistry, and biology into a single subject across Grade 10 and 11.

• Factors that increase reaction rate: higher temperature, higher concentration, smaller particle size, catalyst
• Exothermic reactions release energy to surroundings (combustion, neutralisation, respiration)
• Endothermic reactions absorb energy from surroundings (photosynthesis, thermal decomposition)
• Law of Conservation of Mass: total mass of reactants = total mass of products

Must know

• Exothermic: releases heat (combustion, neutralisation); ΔH < 0
• Endothermic: absorbs heat (thermal decomposition); ΔH > 0
• Activation energy: minimum energy needed to start reaction
• Collision theory: reaction occurs when particles collide with sufficient energy

Source: NIE O/L Science Grade 11 — Unit 3: Chemical Reactions

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In the Syllabus