Experimental techniques and chemical analysis — IGCSE Sciences - Co-Ordinated (0654) questions by topic
Matching substances to separation methods such as chromatography, crystallisation, distillation and fractional distillation, reading a paper chromatogram of food dyes, and identifying a substance used to test for a specific ion sit behind the 6 experimental techniques and chemical analysis questions from 2023 and 2024, worth 8 to 12 marks.
Identify, state and describe lead the command words, with complete and calculate covering the numerical side of separation, such as working from a chromatogram's measurements. Because naming the wrong solvent or method here tends to cascade into a wrong Rf value or conclusion, submit your chromatography and separation answers for instant marking so any mismatched substance-to-method pairing is flagged straight away.
What examiners look for
- Examiners note copper or sulfur were common incorrect suggestions where the correct solvent was required.
- A recurring criticism is that very few candidates could suggest a use for bitumen, such as road surfacing.
- Reports describe many answers on this topic as too vague to be creditable.
- Few candidates knew that an electrolyte works by containing free-moving ions.
October–November 2024, Paper 32
Choose from the following substances to answer the questions (each substance may be used once, more than once or not at all): aluminium, chlorine, copper(II) sulfate, ethanol,…
Answer this question and get it marked →October–November 2024, Paper 33
Choose from the following substances to answer the questions (each substance may be used once, more than once or not at all): aluminium, chlorine, copper(II) sulfate, ethanol,…
Answer this question and get it marked →May–June 2023, Paper 31
Substances are separated from mixtures using different methods. Draw one straight line from each substance to the correct method of separating it from the mixture (one line drawn…
Answer this question and get it marked →Limestone is insoluble in water. Limestone is mixed with water and poured through filter paper. Explain how filter paper separates limestone from water.
Answer this question and get it marked →October–November 2023, Paper 33
There are different methods of separating mixtures. Fig. 2.1 shows that distillation is used to separate water from aqueous potassium chloride. The methods listed are…
Answer this question and get it marked →October–November 2023, Paper 42
A scientist investigates food colourings using paper chromatography. Fig. 11.1 shows the chromatogram produced. The result for dye A is not shown. The chromatogram shows dyes A,…
Answer this question and get it marked →Other IGCSE Sciences - Co-Ordinated topics
- Practical skills (146)
- Motion, forces and energy (41)
- Organic chemistry (16)
- Electricity and magnetism (15)
- Waves (14)
- Reproduction (13)
- Nuclear physics (13)
- Coordination and response (12)
- Organisms and their environment (12)
- Metals (11)
- Atoms, elements and compounds (10)
- Stoichiometry (9)