Measurement and Apparatus
Measurement for IGCSE Chemistry 0620: choosing burette, pipette or measuring cylinder, plus balances, thermometers and gas syringes with precision.
The IGCSE Chemistry Specialist Team · founded by Rig
Written to the Cambridge IGCSE Chemistry (0620) syllabus and mark-scheme conventions. Last updated 2026-06-11.
Paper 6 opens with apparatus questions almost every series (name the equipment from a diagram, or justify choosing a burette over a measuring cylinder), and Paper 5 marks your plan partly on whether the apparatus matches the precision the method needs. These are gift marks for candidates who know what each instrument measures and how finely.
What measures what
| Quantity | Apparatus | Typical precision |
|---|---|---|
| Time | stopwatch / stop-clock | 0.1 s (1 s is fine for rates work) |
| Temperature | thermometer | 0.5-1°C |
| Mass | electronic balance | 0.01 g or 0.1 g |
| Volume of liquid (approximate) | measuring cylinder | ±0.5-1 cm³ |
| Volume of liquid (fixed, accurate) | volumetric pipette | ±0.06 cm³ at 25.0 cm³ |
| Volume of liquid (variable, accurate) | burette | reads to 0.05 cm³ |
| Volume of gas | gas syringe | ±0.5-1 cm³ |
The pattern Cambridge tests: match the apparatus to the accuracy the experiment needs. Rinsing a precipitate? A measuring cylinder is fine. Titrating? Nothing but burette and pipette will do.
The three volume instruments
Measuring cylinder: quick and approximate. Choose it when the volume only needs to be roughly right: adding excess acid, making up a rates experiment where the same cylinder is used each run.
Volumetric pipette: one fixed volume, delivered with high accuracy. The 25.0 cm³ pipette fills to a single calibration line, drained by gravity with the tip touched against the flask wall. Always used with a pipette filler, never by mouth.
Burette: variable volumes, read to 0.05 cm³, with a tap for dropwise control. The reading is taken from the bottom of the meniscus at eye level, and the volume delivered is final reading minus initial reading. Quote burette values to two decimal places ending in 0 or 5 (e.g. 24.35 cm³). Titration technique itself is examined under acids, bases and salts; the apparatus choice is examined here.
Gases, mass and temperature
Gas syringe: the standard way to measure gas volume against time in rates experiments. The alternative, collecting over water in an inverted measuring cylinder, fails for soluble gases (ammonia, sulfur dioxide, hydrogen chloride), a favourite “explain why” mark.
Balance: for mass-loss rates experiments (a flask on a balance losing CO2) and for weighing reactants. A 2 d.p. balance is more precise than a 1 d.p. balance; saying so, with the numbers, earns improvement marks.
Thermometer: read at eye level, bulb fully in the liquid. In enthalpy-style experiments the marking point is recording the maximum (or minimum) temperature reached, not the temperature at a fixed time.
Method-level skills (tables, graphs, anomalous points) are covered in the Paper 6 alternative-to-practical guide; this page is the apparatus layer underneath them.
Worked exam question
A student investigates the rate of reaction between magnesium and dilute hydrochloric acid by measuring the volume of hydrogen produced. (a) Name the apparatus used to measure the volume of gas. [1] (b) The method says “measure 50 cm³ of dilute hydrochloric acid”. State the most suitable apparatus and justify your choice. [2] (c) Suggest why a burette and pipette are not needed in this experiment. [1]
Model answer, mark by mark:
- (a) M1: gas syringe (or: inverted measuring cylinder/burette of water; hydrogen is insoluble, so both score).
- (b) M2: measuring cylinder. M3: the volume does not need to be highly accurate / it only needs to be the same each run, and a measuring cylinder measures 50 cm³ quickly to within about 1 cm³.
- (c) M4: the acid is in excess / the experiment compares rates, so small volume errors do not affect the result, so high-accuracy apparatus is unnecessary.
The justification marks reward matching precision to purpose, not reciting that burettes are “more accurate” in the abstract.
The mistakes that cost marks
- “Beaker” offered as measuring apparatus. Beakers and flasks hold liquids; their graduations are decorative. Naming one for a volume measurement scores zero.
- Burette readings to one decimal place. Cambridge expects 0.05 cm³ precision: 24.30, not 24.3. In Paper 6 table questions this is a stated marking point.
- Collecting soluble gases over water. Ammonia measured in an inverted cylinder of water dissolves on the way up. Name the gas syringe and say why.
- Pipette described as adjustable. A volumetric pipette delivers one fixed volume. “Measure 37 cm³ with a pipette” is an apparatus error. That job belongs to a burette.
How examiners want it phrased
| Student wording | Mark-scheme wording |
|---|---|
| ”Use a burette because it’s accurate" | "Use a burette because it measures variable volumes to the nearest 0.05 cm³" |
| "Read the burette carefully" | "Read the bottom of the meniscus at eye level" |
| "Use a better balance" | "Use a balance reading to 0.01 g instead of 0.1 g" |
| "Collect the gas in a tube" | "Collect the gas in a gas syringe and record the volume at timed intervals” |
Apparatus choice runs under everything in experimental techniques and chemical analysis: separation, chromatography, the lot. If Paper 6 is on your timetable and these marks still feel like guesswork, a free trial lesson working through one past ATP paper will show you how mechanical they really are.
Test yourself
Answer all three without checking the table. Click to reveal each answer.
Q1 (2 marks). A titration requires exactly 25.0 cm³ of sodium hydroxide solution in the flask. Name the most suitable apparatus and justify your choice.
Show answer
• volumetric pipette [1] • it delivers one fixed volume (25.0 cm³) with high accuracy; a measuring cylinder is only accurate to about 1 cm³ [1]
Q2 (2 marks). A student plans to collect ammonia gas over water in an inverted measuring cylinder. Explain why this fails and name suitable apparatus.
Show answer
• ammonia is soluble in water, so it dissolves instead of collecting [1] • use a gas syringe [1]
Q3 (2 marks). State two rules for reading and recording a burette volume correctly.
Show answer
• read the bottom of the meniscus at eye level [1] • record to the nearest 0.05 cm³, i.e. two decimal places ending in 0 or 5 (e.g. 23.45 cm³) [1]
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Frequently asked questions
When do I choose a burette over a measuring cylinder?
When the volume must be measured precisely or delivered variably: a burette reads to 0.05 cm³ and lets you add solution drop by drop. A measuring cylinder is fine when the question says 'approximately' or the volume just needs to be in excess.
What does a pipette do that a burette doesn't?
A volumetric pipette delivers one fixed volume (typically 25.0 cm³) very accurately. A burette delivers any variable volume up to 50 cm³. In a titration you pipette the fixed solution into the flask and run the other from the burette.
How do I measure the volume of gas produced in a reaction?
Collect it in a gas syringe, or in an inverted measuring cylinder (or burette) filled with water, but use the syringe if the gas is soluble in water, such as ammonia or sulfur dioxide.