Science lesson plan · 12th grade (Year 13 in England) · 45 minutes
Titration calculations
Chemical reactions, acids and bases
CCSS NGSS.HS-PS1-7CCSS NGSS.SEP 5England: GCSE Chemistry: Chemical changes (titrations, Higher)
Objective and success criteria
Students will: Titration calculations.
- 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: Concentration in mol/dm³; Neutralisation and naming salts
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 (Concentration in mol/dm³; Neutralisation and naming salts). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 0.1 mol of hydrochloric acid is in 500 cm³ of solution. What is the concentration, in mol/dm³? → 0.2 mol/dm³Prompt: concentration = moles ÷ volume in dm³
- Name the salt: sodium hydroxide + sulfuric acid → ___ + water (sodium chloride / sodium oxide / sodium sulfate / sodium nitrate) → sodium sulfatePrompt: The first part of the salt's name comes from the metal.
- How many moles of sodium hydroxide are in 100 cm³ of a 0.5 mol/dm³ solution? → 0.05 molPrompt: moles = concentration × volume in dm³
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: Titration calculations. 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: 20 cm³ of 0.5 mol/dm³ sodium hydroxide is neutralised by 12.5 cm³ of hydrochloric acid. HCl + NaOH → NaCl + H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places.
- Step 1: n(NaOH) = 0.5 × 0.02 = 0.01
- Step 2: n(HCl) = 0.01
- Step 3: 0.01 ÷ 0.0125 = 0.8
- Step 4: So the answer is: 0.8 mol/dm³
- Answer: 0.8 mol/dm³
- 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.
- 20 cm³ of 0.2 mol/dm³ sodium hydroxide is neutralised by 40 cm³ of hydrochloric acid. HCl + NaOH → NaCl + H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places. → 0.1 mol/dm³Prompt: Find moles of sodium hydroxide: concentration × volume in dm³.
- Titres (cm³): rough 23.76, run 1 22.71, run 2 22.61. Ignoring the rough titre, calculate the mean titre from the concordant results (within 0.10 cm³), in cm³. Give 2 decimal places. → 22.66 cm³Prompt: The rough titre is only a guide.
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.
- 25 cm³ of 0.2 mol/dm³ sodium hydroxide is neutralised by 40 cm³ of sulfuric acid. H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O. What is the concentration of the acid, in mol/dm³? Give 3 decimal places. → 0.063 mol/dm³Prompt: Find moles of sodium hydroxide: concentration × volume in dm³.
- Why is acid added dropwise near the end point? (to keep the burette full / because drops react faster / to make the indicator brighter / to avoid adding too much past the end point) → to avoid adding too much past the end pointPrompt: One drop can change the colour.
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: Concentration in mol/dm³.
- 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-12.
Free lesson plan from eurekami.com/lesson-plan-builder