Science lesson plan · 10th grade (Year 11 in England) · 45 minutes
Calculate mean rates of reaction from data
Chemical reactions, acids and bases
CCSS NGSS.HS-PS1-5CCSS NGSS.SEP 5England: GCSE Combined Science: The rate and extent of chemical change
Objective and success criteria
Students will: Calculate mean rates of reaction from data.
- 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: Rates of reaction
Leads to: the next skill in this area.
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 · 5 min
- Quick retrieval from earlier learning (Rates of reaction). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A reaction produces 200 cm³ of gas in 50 seconds. What is the mean rate of reaction, in cm³/s? → 4 cm³/sPrompt: mean rate = amount of product ÷ time
- Why does a more concentrated acid react faster? (It has a lower pH so no collisions are needed / It is hotter / There are more acid particles in the same volume, so collisions are more frequent / The particles are heavier) → There are more acid particles in the same volume, so collisions are more frequentPrompt: Concentration is how crowded the particles are.
- Rates of reaction: which statement is NOT true? (Food lasts longer in a fridge because reactions are slower at low temperature. / Reactions need particles to collide with enough energy. / Every collision between particles causes a reaction. / Increasing surface area increases the rate.) → Every collision between particles causes a reaction.Prompt: What does a catalyst change, and what does it not change?
Hook · 5 min
- Drop an antacid tablet in water (or show a clip) and ask whether a new substance is being made.
- Share the objective: Calculate mean rates of reaction from data. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Magnesium reacted with acid and 24 cm³ of hydrogen was collected in 20 s. What was the mean rate of reaction, in cm³/s?
- Step 1: 24 ÷ 20 = 1.2
- Step 2: So the answer is: 1.2 cm³/s
- Answer: 1.2 cm³/s
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Magnesium reacted with acid and 90 cm³ of hydrogen was collected in 60 s. What was the mean rate of reaction, in cm³/s? → 1.5 cm³/sPrompt: mean rate = amount of product formed ÷ time taken
- Marble chips and acid were placed on a balance. The mass fell from 120 g to 118.5 g in 150 s as carbon dioxide escaped. What was the mean rate of reaction, in g/s? Give 3 decimal places. → 0.01 g/sPrompt: First find the mass of gas lost.
You do: independent practice · 10 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 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Marble chips and acid were placed on a balance. The mass fell from 162.4 g to 160.6 g in 300 s as carbon dioxide escaped. What was the mean rate of reaction, in g/s? Give 3 decimal places. → 0.006 g/sPrompt: First find the mass of gas lost.
- Volume of gas collected: 0 s: 0 cm³; 20 s: 18 cm³; 40 s: 28 cm³; 60 s: 33 cm³; 80 s: 36 cm³; 100 s: 38 cm³. What was the mean rate between 0 s and 20 s, in cm³/s? Give 2 decimal places. → 0.9 cm³/sPrompt: Find the change in volume over that time interval.
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: Rates of reaction.
- 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
- 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