IB MYP Sciences – States and properties of matter Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – the IB holds copyright in its own papers. Use these alongside the official past papers available through your school or the IB store.

These practice questions cover states and properties of matter for IB MYP Sciences. They are aligned to the International Baccalaureate Organization, Middle Years Programme Subject Brief – Sciences, from 2014, which lists this topic among those explored in the on-screen examinations. MYP has no SL/HL levels; the set suits MYP years 4 and 5. MYP has no prescribed content list – schools design their own units – so this page covers a topic the brief names.

Each question names the criterion it mainly trains. Real MYP work is judged against criterion level descriptors (levels 1–8 in four bands), so the [1] points below are a revision aid, not IB marks. Your teacher will share the task-specific clarifications for real tasks. All data is invented. Use a calculator for questions 2, 3, 7 and 9.

Revise first from the study guide or revision notes. Also see the IB MYP Sciences hub · printable checklist.

Questions

1. (Criterion A) A beaker of crushed ice is heated steadily. Its temperature stays at 0 °C until all the ice has melted. Explain why the temperature does not rise while the ice is melting. [3]

2. (Criterion A, calculation) A rectangular metal block measures 5.0 cm × 4.0 cm × 2.0 cm and has a mass of 316 g.

(a) Calculate the density of the metal in g/cm³. [2] (b) Convert your answer to kg/m³. [1] (c) Predict whether the block floats or sinks in water, with a reason. [1]

3. (Criterion C) A measuring cylinder reads 35.0 cm³ before a stone is added and 49.0 cm³ after. The stone’s mass is 36.4 g.

(a) Calculate the density of the stone. [3] (b) Identify one source of error in this method and suggest a specific improvement. [2]

4. (Criterion A) Use the particle model to explain each observation.

(a) The outlet of a syringe of air is blocked. As the plunger is pushed in, it gets harder to push. [3] (b) A sealed metal can of air placed near a fire may burst. [3]

5. (Criterion C) A student melts a sample of a fictional wax, W, and records its temperature every minute as it cools.

Time / min	0	1	2	3	4	5	6	7	8	9	10	11
Temperature / °C	80	72	65	59	55	54	54	54	54	51	46	41

(a) State the freezing point of wax W. [1] (b) State the time interval over which wax W is freezing. [1] (c) Explain why the temperature stays constant during this interval. [2] (d) A second sample of W freezes gradually between 49 °C and 52 °C. Suggest, with a reason, what this shows about it. [2]

6. (Criterion A) Choose the best separation method for each mixture.

(a) Sand from water [1] (b) Copper sulfate crystals from copper sulfate solution [1] (c) Pure water from seawater [1] (d) Ethanol from a mixture of ethanol and water [1] (e) Explain how the method in (d) separates the two liquids. Ethanol boils at 78 °C and water at 100 °C. [2]

7. (Criterion C) A black ink is tested by paper chromatography. The solvent front moves 7.5 cm from the baseline. The ink gives two spots, at 1.5 cm and 4.5 cm from the baseline. Three reference dyes have Rf values: P = 0.20, Q = 0.60, R = 0.80.

(a) Calculate the Rf value of each spot. [2] (b) Deduce which reference dyes are in the ink. [1] (c) Explain why the baseline must be drawn in pencil. [1]

8. (Criterion B, extended) Plan an investigation into how the concentration of salt dissolved in water affects the temperature at which the water boils.

(a) Write a testable hypothesis with a scientific reason. [2] (b) Identify the independent variable, the dependent variable and two control variables. [3] (c) Outline a safe method that would give reliable results. [3]

9. (Criterion C, extended) A solid, Z, is heated by a 50 W heater. Its heating curve is flat from 2.0 to 5.5 min (melting) and from 12.0 to 26.0 min (boiling).

(a) Calculate how many times longer the second flat section is than the first. [2] (b) Calculate the energy supplied by the heater during melting, assuming all of it reaches Z. [2] (c) Use the particle model to explain why boiling needs more energy than melting. [2] (d) Suggest why the energy actually absorbed by Z during melting is less than your answer to (b). [1]

10. (Criterion D, extended) In some hot, dry regions without reliable electricity, vegetables are stored in an evaporative cooler: a clay pot inside a larger one, with wet sand between them and a damp cloth on top.

(a) Use the particle model to explain how the cooler keeps the vegetables cool. [3] (b) Evaluate the cooler for a community, giving one benefit and two limitations, and reach a judgment. [4]

Answers

1. The energy supplied is used to overcome the forces of attraction between the water particles [1], so the particles can leave their fixed positions and move past each other [1]. The energy does not increase the kinetic energy of the particles, so the temperature stays constant until melting is complete [1]. [3] Examiner insight: “The energy is used for melting” restates the question; credit comes from naming the forces between particles and linking kinetic energy to temperature.

2. (a) Volume = 5.0 × 4.0 × 2.0 = 40 cm³ [1]; density = 316 / 40 = 7.9 g/cm³ [1] (b) 7.9 × 1000 = 7900 kg/m³ [1] (c) It sinks, because 7.9 g/cm³ is greater than the density of water, 1.00 g/cm³ [1] Examiner insight: A density without its unit is incomplete; (c) needs the prediction and the comparison with water.

3. (a) Volume = 49.0 − 35.0 = 14.0 cm³ [1]; density = 36.4 / 14.0 [1] = 2.6 g/cm³ [1] (b) Error: e.g. water splashes out when the stone is dropped in, so the volume reads too small [1]. Improvement: lower the stone gently on a thread [1]. Examiner insight: The improvement must fix the error you named; “be more careful” doesn’t show how the error is reduced.

4. (a) The same number of particles is squashed into a smaller volume [1], so each area of the syringe wall is hit by particles more often each second [1]. More frequent collisions mean higher pressure, which pushes back on the plunger [1]. (b) Heating gives the air particles more kinetic energy, so they move faster [1]. They hit the inside walls of the can more often and with more force [1]. The pressure rises, and if it becomes too high the can bursts [1]. Examiner insight: Each explanation needs the full chain – particles, collisions with the walls, pressure; the collisions step is the one most often missed.

5. (a) 54 °C [1] (b) From 5 min to 8 min [1] (c) As the wax freezes, forces form between the particles and energy is released [1]. This balances the energy lost to the surroundings, so the temperature stays constant until all the wax is solid [1]. (d) The second sample is impure [1]: a pure substance freezes at one fixed temperature, while an impurity lowers the freezing point and spreads it over a range [1]. Examiner insight: In data questions, quote values from the table (54 °C, 5–8 min) rather than describing the trend in general words.

6. (a) Filtration [1] (b) Crystallisation (evaporate some water, then leave to cool) [1] (c) Simple distillation [1] (d) Fractional distillation [1] (e) Ethanol has the lower boiling point, so its vapour reaches the top of the fractionating column first [1]. It is cooled in the condenser and collected, while most water condenses back into the flask [1]. Examiner insight: For (e), use the boiling points; listing apparatus without saying why ethanol comes over first earns little.

7. (a) Spot 1: Rf = 1.5 / 7.5 = 0.20 [1]; spot 2: Rf = 4.5 / 7.5 = 0.60 [1] (b) The ink contains P and Q (not R), because the Rf values match [1] (c) Pencil (graphite) doesn’t dissolve in the solvent, so the line won’t run into the spots [1] Examiner insight: Rf values have no unit and must be between 0 and 1; a value above 1 signals the distances were swapped.

8. (a) Hypothesis: as the salt concentration increases, the boiling temperature of the water increases [1], because dissolved salt is an impurity and impurities raise the boiling point of a liquid [1]. (b) Independent: salt concentration (e.g. 0, 5, 10, 15, 20 g per 100 cm³ of water) [1]. Dependent: boiling temperature in °C, read from a thermometer [1]. Controls: same volume of water (measuring cylinder); same thermometer position, not touching the beaker [1]. (c) Dissolve the salt fully, heat until the water boils steadily, and record the temperature [1]. Repeat each concentration three times and calculate a mean [1]. Safety: wear eye protection and let equipment cool before handling [1]. Examiner insight: Criterion B rewards a plan someone could follow – five stated concentrations and how each control is kept the same beat a bare list of variable names.

9. (a) First section: 5.5 − 2.0 = 3.5 min (210 s); second: 26.0 − 12.0 = 14.0 min (840 s) [1]; 14.0 / 3.5 = 4.0 times longer [1] (b) E = P × t = 50 × 210 [1] = 10 500 J (10.5 kJ) [1] (c) In melting the particles stay close together, so only some forces are overcome [1]; in boiling they are separated completely, which needs far more energy [1]. (d) Some of the heater’s energy heats the container and the surrounding air instead of Z [1]. Examiner insight: Convert minutes to seconds before using E = P × t; 50 × 3.5 = 175 J is wrong by a factor of 60.

10. (a) Water in the wet sand and cloth evaporates [1]. The most energetic particles escape, so the average kinetic energy of the water left behind falls and it cools [1]. Energy then passes from the inner pot and vegetables to the cooler water [1]. (b) Benefit: it keeps food fresh longer without electricity, using cheap local materials [1]. Limitation: it works poorly in humid air, where evaporation is slower [1]. Limitation: it needs regular water, which may be scarce in dry regions [1]. Judgment: a useful low-cost option in hot, dry areas with some water, but not a full substitute for a refrigerator [1]. Examiner insight: Criterion D asks for a judgment backed by the points you made; a list of pros and cons with no conclusion leaves the “evaluate” command unanswered.

Where marks are usually lost

• Saying the temperature rises during melting, freezing or boiling.
• Explaining gas pressure without mentioning collisions with the container walls.
• Saying particles get bigger when a gas or solid is heated.
• Leaving the unit off a density, or using minutes in E = P × t.
• Measuring Rf distances from the paper’s bottom edge instead of the baseline.
• Listing variables in a design task without saying how each control is kept constant.
• Ending an “evaluate” answer without a judgment.

Next steps

• Revision notes for weak areas.
• Study guide for full explanations.
• More design and data practice: criteria in practice questions.
• IB MYP Sciences hub and printable checklist.
• Try all free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

International Baccalaureate Organization, Middle Years Programme Subject Brief – Sciences, from 2014. Published by the International Baccalaureate Organization.