Back to the lesson plan builder
Lesson length30 min45 min60 min
Questions🔀 New questions

Print the plan for yourself; the student sheet prints on its own page after it.

Science lesson plan · 8th grade (Year 9 in England) · 30 minutes

Exothermic and endothermic reactions

Chemical reactions, acids and bases

CCSS NGSS.MS-PS1-6CCSS NGSS.HS-PS1-4England: KS3 Chemistry: EnergeticsEngland: KS4 Combined Science: Energy changes in chemistry

Objective and success criteria

Students will: Exothermic and endothermic reactions.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: Reactants, products and word equations

Leads to: Rates of reaction; Reaction profiles: energy change and activation energy

Materials: Teacher demo or video, Indicator color chart, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 4 min

  • Quick retrieval from earlier learning (Reactants, products and word equations). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Complete the word equation: calcium + oxygen → ___ (calcium chloride / calcium carbonate / calcium oxide / copper oxide) → calcium oxidePrompt: A metal reacting with oxygen makes a metal oxide.
  2. Why does a candle under a glass jar go out? (The oxygen inside is used up / The wax turns into water / Glass puts out flames / The jar gets too heavy) → The oxygen inside is used upPrompt: What does burning use from the air?
  3. Word equations: which statement is NOT true? (Combustion is a reaction with oxygen. / Thermal decomposition breaks a substance down using heat. / The arrow in a word equation means "equals". / Reactants are written on the left of the arrow.) → The arrow in a word equation means "equals".Prompt: Which side of the arrow is which?

Hook · 3 min

  • Drop an antacid tablet in water (or show a clip) and ask whether a new substance is being made.
  • Share the objective: Exothermic and endothermic reactions. Read the success criteria together.

I do: model it · 7 min

  • Work through the example out loud, saying why you do each step, not just what you do.
  • Example: Is this exothermic or endothermic: thermal decomposition of calcium carbonate?
  • Step 1: Endothermic reactions take in energy from the surroundings, so the temperature falls.
  • Step 2: So the answer is: endothermic
  • Answer: endothermic
  • Pause after each step and ask a student to say what comes next.

We do: guided practice · 6 min

  • Do these together. Students try each step on whiteboards before you reveal it.
  • Use the hints as prompts rather than giving the answer.
  1. Is this exothermic or endothermic: respiration? (exothermic / endothermic) → exothermicPrompt: Does it give out heat or take heat in?
  2. The temperature of a reaction mixture changes from 18 °C to 3 °C. What is the temperature change? (Use a minus sign for a fall.) → -15 °CPrompt: Change = final temperature − starting temperature.

You do: independent practice · 7 min

  • Students work on the student sheet. Circulate and check the first two answers of every student early.
  • Students who finish: write a question of their own for a partner, with the answer.

The 6 questions are on the student sheet below, with answers in the key.

Exit ticket · 3 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. Is this exothermic or endothermic: magnesium reacting with acid? (exothermic / endothermic) → exothermicPrompt: Does it give out heat or take heat in?
  2. A self-heating can of coffee uses which kind of reaction? (photosynthesis / endothermic / nuclear / exothermic) → exothermicPrompt: It needs to warm the drink.

Watch out for

  • Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
  • Remembering facts without the reason: ask "why?" and "what is the evidence?"

Support and stretch

Support

  • Review first: Reactants, products and word equations.
  • Use concrete materials: teacher demo or video.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Move on to: Rates of reaction; Reaction profiles: energy change and activation energy.
  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-8.

Free lesson plan from eurekami.com/lesson-plan-builder

eurekami

Exothermic and endothermic reactions

Name

Date

Score/ 6

  1. Question 1

    The temperature of a reaction mixture changes from 20 °C to 16 °C. What is the temperature change? (Use a minus sign for a fall.)

    Answer°C

  2. Question 2

    What is activation energy?

    • A. the energy in a battery
    • B. the minimum energy particles need to react when they collide
    • C. the energy given out by a reaction
    • D. the energy of light

  3. Question 3

    Is this exothermic or endothermic: a self-heating hand warmer?

    • A. exothermic
    • B. endothermic

  4. Question 4

    The temperature of a reaction mixture changes from 18 °C to 29 °C. What is the temperature change? (Use a minus sign for a fall.)

    Answer°C

  5. Question 5

    A self-heating can of coffee uses which kind of reaction?

    • A. photosynthesis
    • B. nuclear
    • C. endothermic
    • D. exothermic

  6. Question 6

    Is this exothermic or endothermic: neutralising an acid with an alkali?

    • A. exothermic
    • B. endothermic

Free from eurekami.com

for the adult only

Answer key: Exothermic and endothermic reactions

  1. 1. -4 °C

  2. 2. B. the minimum energy particles need to react when they collide

  3. 3. A. exothermic

  4. 4. 11 °C

  5. 5. D. exothermic

  6. 6. A. exothermic