C3 C4 part A

According to the particle theory, which statement best describes the particles in a solid?

• They move around randomly and are far apart.

• They are packed closely together and vibrate around fixed positions.

• They can slip and slide over each other in a random arrangement.

• They exert pressure by colliding with the container walls.

Which of the following is a property of liquids?

• They have no fixed volume and can be compressed easily.

• They have a fixed shape and a fixed volume.

• They have a fixed volume but can flow and change their shape.

• They cannot flow and are rigid.

What causes the pressure of a gas in a sealed container?

• The particles vibrating in fixed positions.

• The strong forces between the particles.

• The particles colliding with the sides of the container.

• The particles sticking to the walls of the container.

What happens to the particles when a solid substance melts?

• The particles stop vibrating and start moving randomly.

• The vibrations become so strong that the particles break free from their neighbours.

• The particles become smaller.

• The particles form strong chemical bonds with each other.

What is the name for the change of state when a solid turns directly into a gas without passing through the liquid phase?

• Condensation

• Freezing

• Evaporation

• Sublimation

When observing a heating curve for a pure substance, why does the temperature remain constant at the melting point until all the solid has melted?

• Because the substance stops absorbing energy.

• Because the energy being supplied is used to break the forces between particles, not to raise the temperature.

• Because the thermometer is not working correctly at that temperature.

• Because the liquid is cooling down as the solid melts.

A limitation of the simple particle model is that it assumes particles are solid spheres. In reality, atoms are...

• solid spheres

• not solid spheres; they have internal structure and are mostly empty space.

The model of a solid, liquid, and gas shows that all matter is made up of particles. What does the model suggest about the structure of a gas?

• mostly empty space.

• cube-shaped.

• filled with liquid.

• much larger than the model suggests.

Which statement about the particles in a solid is correct?

• They are arranged in a regular pattern.

• They are free to move around.

• They are far apart.

• They are not affected by temperature.

Substances with higher melting points and boiling points must have...

• weaker forces operating between their particles.

• smaller particles.

• stronger forces operating between their particles.

• particles that are further apart.