Science lesson plan · 9th grade (Year 10 in England) · 60 minutes
Identify gases with laboratory tests
Chemical reactions, acids and bases
CCSS NGSS.HS-PS1-2CCSS NGSS.SEP 3England: GCSE Combined Science: Chemical analysis
Objective and success criteria
Students will: Identify gases with laboratory tests.
- 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: What acids make with metals and carbonates
Leads to: Identify metal ions with flame tests and precipitates
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 · 6 min
- Quick retrieval from earlier learning (What acids make with metals and carbonates). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Zinc reacts with nitric acid. What are the products? (zinc oxide + hydrogen / zinc nitrate + carbon dioxide / zinc nitrate + hydrogen / zinc sulfate + hydrogen) → zinc nitrate + hydrogenPrompt: acid + metal → salt + hydrogen
- Calcium carbonate reacts with hydrochloric acid. What are the products? (calcium carbonate + water / calcium chloride + water + carbon dioxide / calcium chloride + water / calcium chloride + hydrogen) → calcium chloride + water + carbon dioxidePrompt: Carbonates fizz with acids. Which gas turns limewater cloudy?
- Which metal would NOT fizz when placed in dilute hydrochloric acid? (zinc / magnesium / iron / copper) → copperPrompt: Metals below hydrogen in the reactivity series do not react with dilute acids.
Hook · 6 min
- Drop an antacid tablet in water (or show a clip) and ask whether a new substance is being made.
- Share the objective: Identify gases with laboratory tests. Read the success criteria together.
I do: model it · 12 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Which gas gives this result: bubbled through limewater, it turns it milky?
- Step 1: Carbon dioxide turns limewater milky (cloudy).
- Step 2: So the answer is: carbon dioxide
- Answer: carbon dioxide
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Which gas gives this result: a lighted splint gives a squeaky pop? (hydrogen / oxygen / carbon dioxide / chlorine) → hydrogenPrompt: Each common gas has its own test.
- A gas puts out a lighted splint and turns limewater milky. What is it? (chlorine / hydrogen / oxygen / carbon dioxide) → carbon dioxidePrompt: Fire extinguishers sometimes contain this gas.
You do: independent practice · 17 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 · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Why must the chlorine test be done in a fume cupboard? (Chlorine is radioactive / Chlorine is toxic / Chlorine is invisible / Chlorine explodes) → Chlorine is toxicPrompt: Think about safety.
- Which gas gives this result: bubbled through limewater, it turns it milky? (hydrogen / oxygen / carbon dioxide / chlorine) → carbon dioxidePrompt: Each common gas has its own test.
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: What acids make with metals and carbonates.
- 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: Identify metal ions with flame tests and precipitates.
- 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-9.
Free lesson plan from eurekami.com/lesson-plan-builder