IB Middle Years Programme (MYP) · Sciences

States of matter and changes of state: Practice Questions

5 multiple-choice questions marked as you go, and 5 written questions with worked solutions. All on States of matter and changes of state.

10 questions24 marksFree, no account

Question 1

1 mark

Which of the following processes involves a substance changing its state from a gas directly to a solid without becoming a liquid first?

Question 2

1 mark

A sample of a pure substance is heated at a constant rate. The following data shows the temperature of the substance over a period of time:

At 2 minutes: \(40^{\circ}\text{C}\) (Solid)
At 4 minutes: \(80^{\circ}\text{C}\) (Solid and Liquid)
At 6 minutes: \(80^{\circ}\text{C}\) (Solid and Liquid)
At 8 minutes: \(110^{\circ}\text{C}\) (Liquid)

Based on the kinetic theory of matter, what is happening to the particles of the substance between the 4th and 6th minute?

Question 3

1 mark

A substance exists in a closed container at a temperature where it is a liquid. If the temperature is kept constant while the volume of the container is slowly increased, which of the following statements correctly describes the changes in the system at the molecular level once a dynamic equilibrium is established between the liquid and its vapor?

Question 4

1 mark

Which of the following processes involves a substance changing its state from a solid directly to a gas without passing through the liquid phase?

Question 5

1 mark

Which of the following best explains why gases are much more compressible than solids?

Question 6

2 marks

Explain why solids have a high density compared to gases in terms of particle spacing.

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Question 7

3 marks

A sealed rigid metal flask containing a gas at room temperature is placed into an oven. Explain, in terms of particle theory, why the gas pressure inside the container increases as it is heated.

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Question 8

5 marks

Using the Kinetic Molecular Theory, explain why the temperature of a boiling liquid remains constant even though thermal energy is still being added to the system.

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Question 9

4 marks

A student has a sealed syringe containing a fixed amount of air. The syringe is initially at room temperature.

(a) Describe the arrangement and motion of the particles inside the syringe using the kinetic theory of matter.

(b) The student pushes the plunger of the syringe inward, decreasing the volume while keeping the temperature constant. Explain, in terms of particle behavior, why the pressure inside the syringe increases.

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Question 10

5 marks

A sample of a pure substance is heated evenly at a constant rate starting from a solid at time \(t = 0\). The temperature is recorded over time as shown in the heating curve diagram below.

(a) Identify the physical state(s) of matter present during stage QR.
(b) Using the particle model of matter, explain why the temperature remains constant between points Q and R despite continuous heating.
(c) From the diagram, determine the boiling point of the substance.
(d) Compare the kinetic energy and potential energy of the particles as the substance transitions from P to Q versus from Q to R.

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