Chapter 1
Chapter 1: Chemical Reactions and Equations
Chemical reactions, word and symbol equations, balancing, reaction types, energy changes, oxidation and reduction.
6 topics28 skillsWorksheets available
Practice questionsWorksheets availableMore practice coming soonProgress tracking after sign-in
Topic: Chemical Changes and Evidence
4 skillsSkill: Identify observable evidence of a chemical reactionUse clues such as gas evolution, colour change, temperature change, precipitate formation and new substance formation.
Practice areaSkill: Distinguish chemical changes from physical changesClassify changes based on whether a new substance is formed and whether the change is usually reversible.
Practice areaSkill: Infer reactants and products from a reaction descriptionIdentify starting substances and substances formed from a word problem, lab note or diagram.
Practice areaSkill: Explain why everyday processes are chemical changesUse evidence to explain examples such as rusting, burning, curd formation, cooking and digestion.
Practice areaTopic: Chemical Equations
4 skillsSkill: Read chemical equations as statements of reactionsInterpret symbols, formulae, plus signs and arrows as a sentence about a reaction.
Practice areaSkill: Write word equations for simple reactionsConvert a reaction description into a clear word equation with reactants and products.
Practice areaSkill: Convert word equations into skeletal chemical equationsUse correct chemical formulae to write unbalanced symbol equations.
Practice areaSkill: Interpret state symbols in chemical equationsIdentify and use symbols such as solid, liquid, gas and aqueous in reaction equations.
Practice areaTopic: Balancing Equations
5 skillsSkill: Explain conservation of mass while balancing equationsConnect balancing equations with the law of conservation of mass.
Practice areaSkill: Balance simple chemical equations by atom countingUse atom counts on both sides to balance equations with small coefficients.
Practice areaSkill: Balance equations containing polyatomic groupsTreat unchanged polyatomic ions as groups where appropriate while balancing.
Practice areaSkill: Identify errors in incorrectly balanced equationsCheck equations for unequal atom counts and correct coefficient errors.
Practice areaSkill: Balance equations from common laboratory reactionsBalance equations for common Class X reactions such as quicklime with water or copper sulphate with iron.
Practice areaTopic: Types of Reactions
7 skillsSkill: Classify combination reactionsRecognise reactions where two or more reactants form a single product.
Practice areaSkill: Classify decomposition reactionsRecognise reactions where one compound breaks into simpler substances.
Practice areaSkill: Distinguish thermal photolytic and electrolytic decompositionIdentify whether heat, light or electricity causes a decomposition reaction.
Practice areaSkill: Classify displacement reactionsRecognise when a more reactive element displaces a less reactive element from a compound.
Practice areaSkill: Classify double displacement reactionsRecognise exchange of ions between two compounds in solution.
Practice areaSkill: Identify precipitation reactions from productsPredict or recognise formation of an insoluble solid in a reaction.
Practice areaSkill: Classify reactions from observations and equationsUse both observations and balanced equations to decide the reaction category.
Practice areaTopic: Energy Changes in Reactions
3 skillsSkill: Distinguish exothermic and endothermic reactionsClassify reactions based on whether heat is released or absorbed.
Practice areaSkill: Connect temperature change with reaction energyInfer exothermic or endothermic behaviour from temperature observations.
Practice areaSkill: Identify energy changes in daily-life reactionsExplain energy changes in respiration, combustion, photosynthesis and thermal decomposition.
Practice areaTopic: Oxidation and Reduction
5 skillsSkill: Identify oxidation using gain of oxygen or loss of hydrogenRecognise oxidation in simple reactions using oxygen and hydrogen transfer.
Practice areaSkill: Identify reduction using loss of oxygen or gain of hydrogenRecognise reduction in simple reactions using oxygen and hydrogen transfer.
Practice areaSkill: Classify reactions as redox reactionsIdentify reactions in which oxidation and reduction occur together.
Practice areaSkill: Explain corrosion as oxidationConnect rusting and other corrosion examples with oxidation of metals.
Practice areaSkill: Explain rancidity using oxidationDescribe how oxidation spoils fats and oils and how antioxidants or storage methods reduce it.
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