Science lesson plan · 10th grade (Year 11 in England) · 45 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 · 5 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: a solution in which no more solute will dissolve? (insoluble / solution / solute / saturated solution) → saturated solutionPrompt: Solute + solvent → solution.
- Convert 10 cm into mm. → 100 mmPrompt: How many mm are in 1 cm?
- 5 g of salt is dissolved in 250 g of water. What is the mass of the solution, in g? → 255 gPrompt: Does the salt's mass disappear when it dissolves?
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: Concentration in grams per dm³. 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: 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 · 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.
- 125 g of sodium hydroxide is dissolved to make 2.5 dm³ of solution. What is the concentration, in g/dm³? → 50 g/dm³Prompt: concentration = mass of solute ÷ volume of solution
- 10 g of copper sulfate is dissolved in water to make 250 cm³ of solution. What is the concentration, in g/dm³? (1 dm³ = 1000 cm³) → 40 g/dm³Prompt: Convert cm³ to dm³ by dividing by 1000.
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.
- 3 g of sodium hydroxide is dissolved to make 0.25 dm³ of solution. What is the concentration, in g/dm³? → 12 g/dm³Prompt: concentration = mass of solute ÷ volume of solution
- What mass of glucose is needed to make 400 cm³ of solution with a concentration of 50 g/dm³, in g? → 20 gPrompt: mass = concentration × volume (in dm³)
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