Grade 9 - Particle Model

A block of ice is heated at a constant rate. Eventually the melted ice boils.

The graph shows how the temperature changes with time.

How many minutes did it take to melt all the ice?

• 4

• 7

• 11

• 13

A substance can exist in three different states: solid, liquid or gas. Each of the two statements below describes a change of state.

change 1 Molecules move closer together but continue to travel throughout the substance.

change 2 Molecules stop travelling throughout the substance and just vibrate about fixed positions.

Which changes of state do these statements describe?

• change 1 - condensation

  change 2 - melting

• change 1 - condensation

  change 2 - freezing

• change 1 - freezing

  change 2 - condensation

• change 1 - freezing

  change 2 - melting

The diagram shows a cup of tea.

Which answer describes the water particles in the air above the cup (steam) compared with the water particles in the cup?

• water in the air above the cup is moving faster and particles are closer together than the water particles in the cup.

• water in the air above the cup is moving faster and particles are farther apart than the water particles in the cup.

• water in the air above the cup is moving slower and particles are closer together than the water particles in the cup.

• water in the air above the cup is moving slower and particles are farther apart than the water particles in the cup.

In which changes do the particles move further apart?

• W and X

• W and Z

• X and Y

• Y and Z

An attempt was made to compress a gas and a solid using the apparatus shown.

Which substance would be compressed and what is the reason for this?

• gas because the gas particles are close together

• gas because the gas particles are far apart

• solid because the solid particles are close together

• solid because the solid particles are far apart

The diagram shows how the arrangement of particles changes when a substance changes state.

Which change of state is shown?

• boiling

• condensation

• evaporation

• melting

In which of the following are the particles arranged in a regular pattern?

• a gas

• a liquid

• a metal

• a solution

The diagrams show the arrangement of particles in three different physical states of substance X.

Which statement about the physical states of substance X is correct?

• Particles in state 1 vibrate about fixed positions.

• State 1 changes to state 3 by boiling.

• State 1 changes to state 3 by condensation.

• The substance in stage 3 has a fixed volume.