IGCSE Co-ordinated Sciences (Double Award) 0654 · Chemistry · 163

0654.C12.5.01 — Describe tests to identify the anions: (a). carbonate, CO32–, by reaction with dilute acid and then testing for carbon dioxide gas (b). chlo: past paper questions

5 real questionsasked in 3 of the last 10 exam series2019–2025usually: Which, What, State

Real questions on 0654.c12.5.01 — describe tests to identify the anions: (a). carbonate, co32–, by reaction with dilute acid and then testing for carbon dioxide gas (b). chlo

The newest 5 of 5 written questions. Open one to see it on the real paper.

0654/02 · Specimen 2025 · Q27[1]
What is observed when aqueous silver nitrate is added to this mixture?
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0654/32 · May/June 2025 · Q8b(iii)[1]
At the end of the experiment, the student separates the unreacted solid calcium carbonate from the calcium chloride solution. State the method of separation that the student uses.
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0654/42 · May/June 2025 · Q6e[2]
Carbon dioxide is a simple molecular compound. Tick (3) two properties of simple molecular compounds. good electrical conductivity when molten high boiling point low melting point malleable
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0654/11 · May/June 2024 · Q18[1]
Which substance causes this colour change?
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0654/22 · October/November 2019 · Q23[1]
type of substance is Y?
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What examiners said

Many candidates gave the correct answer, others suggested alternative methods of separation which were not applicable in this case.
— Examiner report, May/June 2025, 0654/32 Q8(b)(iii) (Cambridge)

There was some evidence that some candidates did not understand the information given in this question. However, there was enough information for them to deduce that Y was an alloy, rather than an ionic compound.
— Examiner report, October/November 2019, 0654/22 Q23 (Cambridge)

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In the syllabus

163 0654.C12.5.01 — Describe tests to identify the anions: (a). carbonate, CO32–, by reaction with dilute acid and then testing for carbon dioxide gas (b). chlo

Describe tests to identify the anions: (a). carbonate, CO32–, by reaction with dilute acid and then testing for carbon dioxide gas (b). chloride, Cl –, bromide, Br –, and iodide, I –, by acidifying with dilute nitric acid then adding aqueous silver nitrate (c). nitrate, NO3 –, reduction with aluminium foil and aqueous sodium hydroxide and then testing for ammonia gas (d). sulfate, SO42–, by acidifying with dilute nitric acid and then adding aqueous barium nitrate
Describe tests using aqueous sodium hydroxide and aqueous ammonia to identify the aqueous cations: (a). ammonium, NH4+ (b). calcium, Ca2+ (c).copper(II), Cu2+ (d).iron(II), Fe2+ (e).iron(III), Fe3+ (f). zinc, Zn2+ (formulas of complex ions are not required)
Describe tests to identify the gases: (a). ammonia, NH3, using damp red litmus paper (b). carbon dioxide, CO2, using limewater (c). chlorine, Cl 2, using damp litmus paper (d). hydrogen, H2, using a lighted splint (e). oxygen, O2, using a glowing splint
Describe the use of a flame test to identify the cations: (a). lithium, Li+ (b). sodium, Na+ (c). potassium, K+ (d).copper(II), Cu2+

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