Science lesson plan · 10th grade (Year 11 in England) · 30 minutes
Concentration in grams per dm³
Chemical reactions, acids and bases
CCSS NGSS.HS-PS1-7England: GCSE Combined Science: Quantitative chemistry
Objective and success criteria
Students will: Concentration in grams per dm³.
- 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: Solutes, solvents and how much will dissolve; Converting units
Leads to: Concentration in mol/dm³
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 (Solutes, solvents and how much will dissolve; Converting units). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which word describes this: the sugar stirred into tea? (solute / insoluble / solvent / saturated solution) → solutePrompt: Solute + solvent → solution.
- Convert 3 kg into g. → 3000 gPrompt: How many g are in 1 kg?
- 25 g of salt is dissolved in 200 g of water. What is the mass of the solution, in g? → 225 gPrompt: Does the salt's mass disappear when it dissolves?
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: Concentration in grams per dm³. 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: 10 g of sodium hydroxide is dissolved to make 0.5 dm³ of solution. What is the concentration, in g/dm³?
- Step 1: 10 ÷ 0.5 = 20
- Step 2: So the answer is: 20 g/dm³
- Answer: 20 g/dm³
- 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.
- 18 g of sodium hydroxide is dissolved to make 1.5 dm³ of solution. What is the concentration, in g/dm³? → 12 g/dm³Prompt: concentration = mass of solute ÷ volume of solution
- 4 g of copper sulfate is dissolved in water to make 200 cm³ of solution. What is the concentration, in g/dm³? (1 dm³ = 1000 cm³) → 20 g/dm³Prompt: Convert cm³ to dm³ by dividing by 1000.
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.
- 6 g of sodium hydroxide is dissolved to make 0.5 dm³ of solution. What is the concentration, in g/dm³? → 12 g/dm³Prompt: concentration = mass of solute ÷ volume of solution
- 4 g of copper sulfate is dissolved in water to make 200 cm³ of solution. What is the concentration, in g/dm³? (1 dm³ = 1000 cm³) → 20 g/dm³Prompt: Convert cm³ to dm³ by dividing by 1000.
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: Solutes, solvents and how much will dissolve.
- 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: Concentration in mol/dm³.
- 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