Which statement about the particles in a liquid is correct?
Source: Learners' Alley, Kinetic Particle Theory slides
Which change of state releases energy to the surroundings?
Source: Learners' Alley, Kinetic Particle Theory slides
Why can a gas be compressed, but a liquid cannot?
Source: Learners' Alley, Kinetic Particle Theory slides
A bottle of perfume is opened at one side of a room. Which statement explains why a person on the other side soon smells it?
Source: Learners' Alley, Kinetic Particle Theory slides
Source: Learners' Alley, Kinetic Particle Theory slides
A pure solid is heated steadily until it melts. The temperature stays the same while the solid is melting.
Source: Learners' Alley, Kinetic Particle Theory slides
"Particles moving very slowly from an area of higher concentration to an area of lower concentration." Which process is being described?
Source: 2023 PLMGS Sec 3 End-of-Year P1 Q1
Which statement about evaporation and boiling is not true?
Source: 2026 XMS Sec 3 WA1 P1 Q2
Diagrams of the three states of matter for carbon dioxide are shown below. Which two diagrams show the states of matter before and after the sublimation of carbon dioxide?
Source: 2023 PLMGS Sec 3 End-of-Year P1 Q2
Substance L melts at −7 °C and is a brown liquid at room temperature (25 °C). Which value could be the boiling point of L?
Source: 2023 XMS Sec 3 WA1 P1 Q3
Dry ice sublimes at −78 °C. Which statement describes what happens to dry ice at 0 °C?
Source: 2024 SMSS Sec 3 End-of-Year P1 Q3
Air can be separated into different gases. The air is cooled in stages until it reaches −200 °C. The melting and boiling points of some gases in air are shown in the table.
| gas | melting point / °C | boiling point / °C |
|---|---|---|
| nitrogen | −210 | −196 |
| oxygen | −219 | −183 |
| argon | −189 | −186 |
| carbon dioxide | sublimes at −79 | |
Source: 2026 XMS Sec 3 WA1 P2 Q7(a) to (c), adapted
The graph shows a heating curve of an unknown substance.
Source: 2020 XMS Sec 3 WA1 P2 B2
Fig. 1.1 shows an experimental set-up by a student to determine the rate of diffusion of gases. For this method to work, the gases must only diffuse through the diffusion plug. The time taken for 100 cm3 of the different gases to diffuse through the diffusion plug is recorded in Table 1.2.
| gas | ammonia | argon | carbon monoxide | methane | nitrogen |
|---|---|---|---|---|---|
| relative molecular mass | 17 | 40 | 28 | 16 | 28 |
| time taken for 100 cm3 of gas to diffuse / s | unable to determine | 51 | 32 | 35 | 32 |
Source: 2023 HYSS Sec 3 End-of-Year P2 Q1
BThey are close together and slide past one another.[1]
Liquid particles are closely packed in a disorderly way and slide past one another.
Ccondensation[1]
In condensation the particles lose energy and come closer together. Melting, boiling and sublimation all absorb energy.
BThe particles of a gas are far apart, with a lot of empty space between them.[1]
A gas can be squeezed because its particles are far apart. The particles of a liquid are already touching.
BPerfume particles move randomly and spread from a higher to a lower concentration.[1]
This is diffusion: the net movement of particles from a region of higher concentration to a region of lower concentration.
In a solid the particles are very closely packed in an orderly arrangement, but in a gas they are very far apart in a disorderly arrangement. [1]
In a solid the particles vibrate and rotate about fixed positions, but in a gas they move quickly and randomly in any direction. [1]
Accept the other differences from the lesson, such as kinetic energy or forces of attraction.
The energy absorbed is used to overcome the forces of attraction between the particles. [1]
It is not used to increase the kinetic energy of the particles, so the temperature stays the same. [1]
The particles gain energy and vibrate more quickly. [1]
They move slightly further apart, so the solid expands. [1]
Ca substance diffusing through a liquid[1]
Movement from a higher to a lower concentration is diffusion. The words "very slowly" show that it is through a liquid, because gas particles move rapidly.
DEvaporation only occurs at room temperature, while boiling only occurs at the boiling point.[1]
Evaporation can occur at any temperature, not only at room temperature.
B3 to 1[1]
Sublimation is a solid changing straight to a gas. Diagram 3 is the solid and diagram 1 is the gas.
D59 °C[1]
L is a liquid at 25 °C, so its boiling point must be above 25 °C.
BThe carbon dioxide particles become far apart.[1]
0 °C is above −78 °C, so the solid carbon dioxide turns into a gas and its particles become far apart.
Argon and carbon dioxide. [1]
Particles close together in an orderly arrangement, with at least 3 by 3 particles. [1]
Nitrogen is a solid at −300 °C, because this is below its melting point of −210 °C.
The particles change from sliding past one another to moving rapidly in any direction. [1]
The particles change from being close together and disorderly to being far apart and disorderly. [1]
Oxygen boils at −183 °C, so it changes from a liquid to a gas.
100 °C [1]
250 °C [1]
Solid [1]
Solid and liquid [1]
Gas [1]
As the temperature increases, the particles gain energy [1] and move faster. [1]
When the temperature is high enough, the particles have sufficient energy to overcome the forces of attraction. [1]
The particles are spread far apart and can move about rapidly in all directions. [1]
The mistake is in methane. [1]
The lower the relative molecular mass, the faster the rate of diffusion. Methane has a lower relative molecular mass than carbon monoxide and nitrogen, so it should diffuse in less than 32 s, but the data shows 35 s. [1]
Ammonia is soluble in water. [1]
The molecules are closely packed in a disorderly (irregular) manner [1]
and slide past one another. [1]