Chapter5_Pastpaper

Which of these sentences about water incorrect?

• Stem condenses to make water vapor

• The boiling of water is an irreversible process

• The freezing point of water is the same as the melting point of ice.

• Water evaporates to make ice

Chen opens a bottle of liquid perfume.

After a few seconds he can smell the perfume.

Some of the liquid perfume evaporates into a gas.

The perfume gas then diffuses.

What happens to the particles of perfume during diffusion?

• The particles have less energy

• The particles move closer together

• The particles move more slowly

• The particles spread out

Sublimation is a reversible change.

Complete the following sentence about sublimation.

Some substance like iodine and graphite do not melt when heated but change straight from…….

• Solid to gas

• Solid to liquid

• Gas to liquid

• Liquid to gas

Lavender oil vapour and water vapour cool as they pass down the copper tube.

what is the change in the physical state of both lavender oil vapour an water vapour as they cool?

From __________ to _____________.

• gas to liquid

• liquid to gas

• liquid to solid

• solid to liquid

Rosie poured some lavender oil into an oil burner. She heated it with a candle.

Which diagram represent this change of state?

choose the correct letter

• A

• B

• C

• D

Kate made some ice cubes from pure water. She used a sensor to measure the temperature of the ice.

What temperature will the sensor show when the ice is melting?

• 0 degree

• 100 degree

• 25 degree

• -50 degree

What is the boiling point of water?

• 0 degree C

• 100 degree C

• 25 degree C

• -50 degree C

Which of the following best describes what happens to the particles of water when it evaporates?

• Thy gain energy and loose freedom to move about.

• Thy lose energy and escape into the atmosphere.

• They lose energy and loose freedom to move about.

• They gain energy and increase their freedom to move without any attraction.

The diagram shows a kettle of boiling water.

As the water vapor cools it turns into droplets of liquid water.

The change of state when water vaper changes into liquid is described as …… Thick your answer.

• Boiling

• Condensation

• Evaporation

• Sublimation

Air is in a bottle with a tight screw – top.

When the bottle becomes warmer, the pressure inside increases because the particles of air _____________________________.

• Move slower

• Become smaller

• Become bigger

• Move faster