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      Chemical reactions: acid and metal carbonate

      Lesson details

      Learning outcome

      I can describe what happens when a metal carbonate reacts with an acid and write chemical equations to describe these reactions.

      Key learning points

      1. A group of one carbon atom and three oxygen atoms bonded together is called a carbonate group.
      2. Metal carbonate + acid → salt + water + carbon dioxide
      3. The test for carbon dioxide gas is to bubble it through limewater as it turns the solution cloudy (milky).
      4. Rain water is usually a little acidic and when it is more acidic than normal it is called acid rain.
      5. Acid rain reacts with marble to produce a salt, water and carbon dioxide, using up some of the marble.

      Keywords

      • Chemical weathering - when rocks are broken down by a chemical change, for example reactions with acid rain

      • Limewater - a colourless solution which is used to test for carbon dioxide. It turns cloudy/milky white when carbon dioxide is bubbled through it

      • Chemical test - when a chemical reaction is carried out to determine the presence of a substance

      • Acid rain - rainwater that is more acidic than usual due to air pollution, usually caused by sulfur dioxide and nitrogen oxides

      Common misconception

      Pupils think that acids ‘eat away’ materials and disappear. They observe reactions and see the loss of a reactant, but do not recognise the formation of a new soluble product.

      Ensure that pupils understand the concept of solubility and use the words soluble and dissolve when describing the production of metal salts during these reactions.

      Teacher tip

      Different metal carbonates can also be tested during the practical to show that carbon dioxide is produced by all carbonates. Give each group a different carbonate and pool results to save time.

      Equipment

      Limewater, conical flask with bung and delivery tube, acid, clamp and stand, test tube, test tube rack.

      Content guidance

      Risk assessment required - equipment

      Supervision

      Adult supervision required

      Licence

      This content is © Oak National Academy Limited (2026), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

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      Prior knowledge starter quiz

      6 Questions

      Q1.
      Match the following chemical symbols/formulae to their name.

      Correct Answer:C,carbon
      Correct Answer:Ca,calcium
      Correct Answer:O₂,oxygen
      Correct Answer:CO₂,carbon dioxide

      Q2.
      Match the following key terms to their definitions.

      Correct Answer:aqueous solution (aq),formed when a substance is dissolved in water
      Correct Answer:solvent,a liquid in which a solute dissolves
      Correct Answer:metal salt,a compound formed when an acid reacts with a base
      Correct Answer:neutralisation,when an acid and a base react to produce a neutral solution

      Q3.
      The word used to describe the release of gas from a chemical reaction in a solution is .

      Correct Answer: effervescence, fizzing, bubbling, effervescing

      Q4.
      When sodium hydroxide is added to hydrochloric acid, what happens to the pH of the solution?

      Correct answer: it increases
      it decreases
      it stays the same
      it becomes pH7

      Q5.
      Which of the following equations is the general equation for a neutralisation reaction?

      Correct answer: acid + base → metal salt + water
      acid + base → metal salt + hydrogen
      acid + base → metal + water
      acid + base → salt + water

      Q6.
      A pupil investigates the neutralisation of hydrochloric acid with sodium hydroxide. They add two drops of universal indicator to the solution, which turned blue. What does this tell them?

      Correct answer: The pupil has added too much sodium hydroxide.
      Correct answer: The solution is alkaline.
      The pupil has added too much hydrochloric acid.
      The pupil has used the wrong indicator.

      6 Questions

      Q1.
      Which of the following is the correct formula for a carbonate group?

      CO₁
      CO₂
      Correct answer: CO₃
      C₂O₃

      Q2.
      metal ________ + acid → metal salt + water + carbon dioxide

      base
      oxide
      nitrate
      Correct answer: carbonate
      sulfate

      Q3.
      Match the following gases to the chemical test for that gas.

      Correct Answer:hydrogen,produces a squeaky pop
      Correct Answer:oxygen ,relights a glowing splint
      Correct Answer:carbon dioxide,turns limewater cloudy

      Q4.
      Which of the following statements about rainwater are incorrect?

      Correct answer: Rainwater has a pH of about 4.5.
      Rainwater is naturally slightly acidic.
      Correct answer: Rainwater with a pH higher than 5.6 is called acid rain.
      Rainwater and acid rain both react with marble statues.

      Q5.
      Which of the following are examples of chemical weathering?

      The Sun warming rocks, causing them to expand and crack.
      Correct answer: Limestone rocks being slowly dissolved by acid rain.
      Tree roots growing into cracks in rocks, making them wider so they crack.
      Correct answer: Statues made from calcium carbonate very slowly losing their features.

      Q6.
      Which of the following equations is the correct balanced symbol equation for the reaction between calcium carbonate and hydrochloric acid?

      CaCO₃(s) + 2HCl(l) → CaCl₂(s) + H₂(g) + CO₂(s)
      CaCO₃(s) + HCl(l) → CaCl(s) + H₂O(l) + CO₂(g)
      Correct answer: CaCO₃(s) + 2HCl(aq) → CaCl₂(s) + H₂O(l) + CO₂(g)
      CaCO₃(s) + HCl(aq) → CaCl₂(s) + H₂O(l) + CO₂(g)

      To help you plan your 9 science lesson on: Chemical reactions: acid and metal carbonate, download all teaching resources for free and adapt to suit your pupils' needs...