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 · 10th grade (Year 11 in England) · 30 minutes

Reaction profiles: energy change and activation energy

Chemical reactions, acids and bases

CCSS NGSS.HS-PS1-4England: GCSE Combined Science: Energy changes

Objective and success criteria

Students will: Reaction profiles: energy change and activation energy.

  • 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: Exothermic and endothermic reactions

Leads to: Predict how an equilibrium shifts (Le Chatelier); Calculate energy changes from bond energies

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 (Exothermic and endothermic reactions). Students answer on mini whiteboards.
  • Show answers together and note who needs support in the main task.
  1. Is this exothermic or endothermic: neutralising an acid with an alkali? (exothermic / endothermic) → exothermicPrompt: Does it give out heat or take heat in?
  2. The temperature of a reaction mixture changes from 21 °C to 45 °C. What is the temperature change? (Use a minus sign for a fall.) → 24 °CPrompt: Change = final temperature − starting temperature.
  3. Breaking chemical bonds… (takes in energy (endothermic) / has no energy change / gives out energy (exothermic) / creates new atoms) → takes in energy (endothermic)Prompt: You have to put energy in to pull atoms apart.

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: Reaction profiles: energy change and activation energy. 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: On a reaction profile, the reactants are at 80 kJ, the peak is at 220 kJ and the products are at 140 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)
  • Step 1: 140 − 80 = 60
  • Step 2: Positive: energy is taken in (endothermic).
  • Step 3: So the answer is: 60 kJ
  • Answer: 60 kJ
  • 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. On a reaction profile, the reactants are at 200 kJ, the peak is at 330 kJ and the products are at 230 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.) → 30 kJPrompt: energy change = energy of products − energy of reactants
  2. Reactants: 140 kJ. Peak of the profile: 225 kJ. Products: 110 kJ. What is the activation energy, in kJ? → 85 kJPrompt: Activation energy is the minimum energy needed to start the reaction.

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. On a reaction profile, the reactants are at 80 kJ, the peak is at 180 kJ and the products are at 20 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.) → -60 kJPrompt: energy change = energy of products − energy of reactants
  2. Self-heating cans for camping use a reaction between calcium oxide and water. What type of reaction is this? (endothermic / electrolysis / exothermic / thermal decomposition) → exothermicPrompt: The can gets hot.

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: Exothermic and endothermic reactions.
  • 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: Predict how an equilibrium shifts (Le Chatelier); Calculate energy changes from bond energies.
  • 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-10.

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

eurekami

Reaction profiles: energy change and activation energy

Name

Date

Score/ 6

  1. Question 1

    On a reaction profile, the reactants are at 120 kJ, the peak is at 160 kJ and the products are at 90 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

    AnswerkJ

  2. Question 2

    Reactants: 40 kJ. Peak of the profile: 190 kJ. Products: 60 kJ. What is the activation energy, in kJ?

    AnswerkJ

  3. Question 3

    Self-heating cans for camping use a reaction between calcium oxide and water. What type of reaction is this?

    • A. thermal decomposition
    • B. exothermic
    • C. endothermic
    • D. electrolysis

  4. Question 4

    On a reaction profile, the reactants are at 80 kJ, the peak is at 200 kJ and the products are at 50 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

    AnswerkJ

  5. Question 5

    Reactants: 40 kJ. Peak of the profile: 125 kJ. Products: -10 kJ. What is the activation energy, in kJ?

    AnswerkJ

  6. Question 6

    On a reaction profile, the reactants are at 120 kJ, the peak is at 200 kJ and the products are at 60 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

    AnswerkJ

Free from eurekami.com

for the adult only

Answer key: Reaction profiles: energy change and activation energy

  1. 1. -30 kJ

  2. 2. 150 kJ

  3. 3. B. exothermic

  4. 4. -30 kJ

  5. 5. 85 kJ

  6. 6. -60 kJ