The arrangement of the particles
5 marks · HardThe diagram shows three containers, each containing a different state of a substance at the same temperature.
Give the letter for the container that shows the correct particle arrangement for a solid.
Describe the movement of the particles in the container you identified in part (a).
Explain, using the particle model, why the arrangement of particles in a gas allows a gas to fill any container.
State one reason, based on particle movement, why liquids can flow but solids cannot.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) Solid
(b) Particles vibrate in fixed positions.
(c) — · must show Particles are far apart and arranged randomly., Particles move quickly in all directions and are not held together.
(d) Particles in a liquid can move past each other, but particles in a solid cannot.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly identifies 'Solid' as the container for the solid arrangement.
B2 (b) · 1 mark · Describes the movement of particles in a solid as vibrating about fixed positions only.
M1 (c) · 1 mark · States gas particles are far apart or not held together/random arrangement.
M2 (c) · 1 mark · States gas particles move rapidly in all directions (or freely).
B3 (d) · 1 mark · States that liquid particles can move past each other; solid particles cannot.
Worked solution
a) The correct container is 'Solid' (leftmost), showing regularly arranged, close together particles.
b) In a solid, particles vibrate about fixed positions but do not move from place to place.
c) In a gas, the particles are far apart, randomly arranged, and move quickly in all directions. This means they spread out and fill any space available because there are almost no forces holding them together.
d) Particles in a liquid can move and slide past each other, allowing the liquid to flow, while those in a solid can only vibrate and cannot flow.