Science Chapter 5: Water and Solution

What is the boiling point of water?

• 0 °C
• 100 °C
• 50 °C
• 30 °C

The freezing and melting points of water are the same.

• True
• False

Choose the physical characteristics of water. (You can choose more than one answer.)

• Colourless

• Odourless

• Tasteless

• Acidic

___________________ is an attractive force between the same type of molecules.

• Cohesive force

• Adhesive force

• Friction force

• Drag force

______________________ is an attractive force between different types of molecules.

• Cohesive force

• Adhesive force

• Drag force

• Thrust force

When we add salt into pure water, the boiling point of the solution will

• be more than the boiling point of the pure water.

• be less than the boiling point of the pure water.

• same as the boiling point of the pure water.

Insects like daddy longlegs can move on the surface of the water because of

• the higher density of water.

• the special ability of floating.

• the high surface tension of water.

During evaporation, water molecules on the surface of water ___________________ from surroundings to move faster and then escapes into the air

• obtain energy

• lose energy

• share energy

• produce energy

The higher humidity, the ________________________ the rate of evaporation of water

• lower

• higher

• no change

• changes

The correct application of water evaporation is everyday life are :

• Using hair dryer to dry wet hair.

• Fold the cloth half when hanging to dry.

• Seafood like fish, squids and prawns are dried under the sun

• Close the fan while we sweating