Students classify reactions as exothermic or endothermic from temperature changes and everyday examples such as combustion, respiration, photosynthesis and cold packs. They calculate temperature changes and means from experimental data, use bond-breaking and bond-making energies to decide whether a reaction releases or absorbs energy, interpret energy profile diagrams in words and explain how hand warmers and instant cold packs work.
Instant download · No sign-up · Free for personal, classroom and homeschool use
Curriculum: Australian Curriculum. We show specific outcome codes only where they have been verified against the official curriculum document.
Completed: Exothermic and Endothermic Reactions
Year 9 students (typically ages 14–15) working on mixtures & chemical reactions. It is pitched at level 2 · standard.
Yes. The PDF includes a full answer sheet with model answers and success criteria where there is more than one good answer. You can also view the answers online.
About 40 minutes for 16 questions. Short, regular sessions work best: two or three a week beats one long one.
No. Click Download Free PDF and it opens immediately. It is free for personal, classroom and homeschool use.
Try Combustion, Rusting and Oxidation Reactions.
Success TutoringWorksheetsYear 9 · Science · Mixtures & Chemical ReactionsName
Date
Score /
Exo = energy exits (temperature rises). Endo = energy enters the chemicals (temperature falls).
Classify each reaction.
In an exothermic reaction, energy is released to the surroundings, usually as heat, so the temperature of the surroundings rises. Combustion, respiration and neutralisation are exothermic.
In an endothermic reaction, energy is absorbed from the surroundings, so the temperature falls (or energy must be supplied continuously). Photosynthesis and thermal decomposition are endothermic.
Students measured the starting and highest (or lowest) temperature of two reactions in a foam cup. Reaction 1: magnesium ribbon added to dilute hydrochloric acid: 21 °C → 35 °C. Reaction 2: citric acid solution mixed with sodium hydrogen carbonate (baking soda): 20 °C → 12 °C.
Temperature change = final temperature − initial temperature. A positive change means exothermic; a negative change means endothermic.
In a reaction, bonds in the reactants are broken, which needs energy, and new bonds in the products are made, which releases energy. If more energy is released by making bonds than is taken in to break bonds, the reaction is exothermic. If less is released, it is endothermic.
An energy profile shows the energy of the reactants and products, with a hump between them: the activation energy.
Preview — the PDF contains the full resource and answer sheet.
Students describe the properties of acids and bases, use the pH scale to compare how acidic or basic substances are (including the tenfold…
Students write word and balanced equations for the complete combustion of fuels and the oxidation of metals, compare complete and…
Worksheet · Year 8 · Mixtures & Chemical Reactions · Level 2 · Standard
Worksheet · Year 8 · Mixtures & Chemical Reactions · Level 2 · Standard
Worksheet · Year 10 · Mixtures & Chemical Reactions · Level 3 · Challenge
Worksheet · Year 10 · Mixtures & Chemical Reactions · Level 3 · Challenge
Free to print and share for personal, classroom and homeschool use. Please don't resell. Spotted an error? Let us know.