Cambridge IGCSE · Chemistry 0620
IGCSE Chemistry: Experimental techniques and chemical analysis — Practice Questions & Answers
Measuring accurately, judging purity, separating mixtures, chromatography, and testing for ions and gases.
900 practice questions available for this topic — here are 10 with full answers and explanations.
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Practice questions with answers
1
Multiple choice · Easy
Which piece of apparatus is most suitable for measuring out exactly 25.0 cm3 of a solution?
- A pipette
- A beaker
- A measuring cylinder
- A conical flask
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WhyA pipette delivers a fixed, accurate volume such as 25.0 cm3. Measuring cylinders and beakers are far less precise.
2
Multiple choice · Easy
A pure substance melts sharply at one fixed temperature. What does the presence of impurities do to the melting point of a substance?
- Lowers it and makes it melt over a range
- Raises it and makes it melt over a range
- Has no effect at all
- Keeps it sharp but raises the value
Tap an answer to check it.
WhyImpurities lower the melting point and cause it to melt over a range of temperatures rather than sharply.
3
Multiple choice · Easy
Which separation method is used to obtain an insoluble solid from a liquid?
- Filtration
- Crystallisation
- Chromatography
- Distillation
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WhyFiltration separates an insoluble solid (residue) from a liquid (filtrate) using filter paper.
4
Multiple choice · Easy
Which gas relights a glowing splint?
- Oxygen
- Hydrogen
- Carbon dioxide
- Nitrogen
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WhyOxygen relights a glowing splint. This is the standard test for oxygen gas.
5
Multiple choice · Easy
In paper chromatography, which substance moves up the paper to separate the components of a mixture?
- The solvent
- The pencil baseline
- The filter paper itself
- The locating agent only
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WhyThe solvent (mobile phase) moves up the paper, carrying the dissolved components with it at different rates.
6
Fill in the blank · Easy
A lilac (light purple) flame colour in a flame test indicates the presence of ions.
Answer:
potassium / K+ / potassium (K+)
WhyPotassium ions produce a lilac flame colour in a flame test.
7
Multiple choice · Medium
A few drops of aqueous sodium hydroxide are added to a solution, giving a blue precipitate. Which cation is present?
- Copper(II), Cu2+
- Iron(II), Fe2+
- Iron(III), Fe3+
- Calcium, Ca2+
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WhyCopper(II) ions form a blue precipitate of copper(II) hydroxide with sodium hydroxide solution.
8
Multiple choice · Medium
A solution gives a white precipitate with acidified silver nitrate solution. Which halide ion is present?
- Chloride
- Bromide
- Iodide
- Sulfate
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WhyChloride ions give a white precipitate of silver chloride with acidified silver nitrate solution.
9
Multiple choice · Medium
Which method would best separate pure water from a solution of copper(II) sulfate, collecting the water?
- Simple distillation
- Filtration
- Paper chromatography
- Decanting
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WhySimple distillation evaporates and then condenses the water, leaving the dissolved salt behind in the flask.
10
Multiple choice · Medium
Limewater turns milky (cloudy) when a certain gas is bubbled through it. Which gas is this?
- Carbon dioxide
- Hydrogen
- Ammonia
- Chlorine
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WhyCarbon dioxide turns limewater milky due to the formation of insoluble calcium carbonate.
Key terms in Experimental techniques and chemical analysis
Experimental technique: A practical method used in the laboratory to measure quantities or to separate, purify and identify substances.
Measurement: The process of determining the size of a physical quantity by comparison with a standard unit.
Time measurement: Recording the duration of a process, often using a stopwatch or clock in seconds.
Temperature measurement: Determining how hot or cold a substance is, typically using a thermometer in degrees Celsius.
Thermometer: An instrument used to measure temperature, commonly containing a liquid that expands when heated.
Mass measurement: Determining the amount of matter in a sample, usually using a balance in grams.
Balance: An instrument used to measure the mass of a substance accurately.
Volume measurement: Determining the amount of space a liquid or gas occupies, often in cubic centimetres.
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