IGCSE Chemistry Flashcards

State the main properties of a solid.

Topic: 1.1.States of matter
Answer: A solid has a fixed shape and a fixed volume. It does not flow and is very difficult to compress.

State the main properties of a liquid.

Topic: 1.1.States of matter
Answer: A liquid has a fixed volume but no fixed shape. It flows and takes the shape of the bottom of its container. It is difficult to compress.

State the main properties of a gas.

Topic: 1.1.States of matter
Answer: A gas has no fixed shape and no fixed volume. It spreads out to fill the whole container and is easily compressed.

Compare the volume of solids, liquids and gases.

Topic: 1.1.States of matter
Answer: Solids and liquids have fixed volumes. Gases do not have fixed volumes because their particles are far apart and can spread out.

Compare the shape of solids, liquids and gases.

Topic: 1.1.States of matter
Answer: Solids have a fixed shape. Liquids and gases do not have fixed shapes because their particles can move past each other.

Why are solids and liquids difficult to compress?

Topic: 1.1.States of matter
Answer: Their particles are close together, so there is very little empty space for the particles to move into.

Why are gases easy to compress?

Topic: 1.1.States of matter
Answer: Gas particles are far apart, so there is a lot of empty space between them. Pressure can push the particles closer together.

Describe the particle arrangement in a solid.

Topic: 1.1.States of matter
Answer: Particles are very close together in a regular, fixed arrangement. They vibrate about fixed positions.

Describe the particle motion in a solid.

Topic: 1.1.States of matter
Answer: The particles cannot move from place to place. They only vibrate about fixed positions.

Describe the particle arrangement in a liquid.

Topic: 1.1.States of matter
Answer: Particles are close together but arranged irregularly. They are not fixed in position.

Describe the particle motion in a liquid.

Topic: 1.1.States of matter
Answer: Particles move randomly and can slide past each other. This allows a liquid to flow.

Describe the particle arrangement in a gas.

Topic: States of matter
Answer: Particles are far apart, arranged randomly and have large spaces between them.

Describe the particle motion in a gas.

Topic: 1.1.States of matter
Answer: Particles move rapidly and randomly in all directions. They collide with each other and with the container walls.

Why does a liquid take the shape of its container?

Topic: 1.1.States of matter
Answer: Its particles are close together but can move around and slide past each other, so the liquid flows into the shape of the container.

Why does a gas fill the whole container?

Topic: 1.1.States of matter
Answer: Gas particles move rapidly and randomly in all directions. They are far apart, so they spread out until they occupy all available space.

What is meant by a change of state?

Topic: 1.1.States of matter
Answer: A change of state is a physical change in which a substance changes between solid, liquid and gas without forming a new substance.

Define melting.

Topic: 1.1.States of matter
Answer: Melting is the change of state from solid to liquid, usually when heat energy is supplied.

Explain melting using kinetic particle theory.

Topic: 1.1.States of matter
Answer: Particles gain energy and vibrate more strongly. At the melting point, they have enough energy to overcome some attractive forces and move from fixed positions.

Define freezing.

Topic: 1.1.States of matter
Answer: Freezing is the change of state from liquid to solid, usually when heat energy is removed.

Explain freezing using kinetic particle theory.

Topic: 1.1.States of matter
Answer: Particles lose kinetic energy, move more slowly and become held in fixed positions by attractive forces. A regular solid arrangement forms.

Define boiling.

Topic: 1.1.States of matter
Answer: Boiling is the change of state from liquid to gas throughout the liquid at its boiling point.

Explain boiling using kinetic particle theory.

Topic: 1.1.States of matter
Answer: Particles gain enough energy to overcome the attractive forces between liquid particles. Gas bubbles form throughout the liquid and escape.

Define evaporation.

Topic: 1.1.States of matter
Answer: Evaporation is the change of state from liquid to gas at the surface of a liquid, below the boiling point.

How is evaporation different from boiling?

Topic: 1.1.States of matter
Answer: Evaporation happens only at the surface and can happen below the boiling point. Boiling happens throughout the liquid at a fixed boiling point.