Particle Model of Matter

True or false. ‘Liquids are generally denser than solids and gases’.

• True

• False

True or false. ‘The temperature of a gas is related to the average energy in the kinetic energy stores of its particles’

• True

• False

What is the specific latent heat of fusion?

• The amount of energy needed to melt 1 kg of a substance.

• The amount of energy needed to boil 1 kg of a substance.

• The amount of energy needed to freeze 1 kg of a substance.

The internal energy of a system is equal to…

• …the total energy that its particles have in their kinetic energy stores.

• …the total energy that its particles have in their kinetic and potential energy stores.

• …the total energy that its particles have in their potential energy stores.

What is the specific heat capacity of a substance?

• The energy released by a substance when it freezes.

• The energy needed to raise the temperature of 1 kg of a substance by 1 oC.

True or false. ‘Changes of state are physical changes’.

• True

• False

What happens to the mass of a substance when it changes from a solid to a liquid?

• It increases.

• It decreases.

• It stays the same.

What will happen to the pressure of a fixed volume of gas if its temperature is increased?

• It decreases.

• It increases.

• It stays the same.

A student wanted to determine the density of the irregular shaped object shown in figure 1.

Plan an experiment that would allow the student to determine the density of the object. 6 marks

Figure 2 shows solid ice on a car’s rear window. The glass window contains an electrical element. A car manufacturer tests different heating elements by measuring how long it takes ice to melt. During the test some variable must be controlled. Identify two control variables in the car manufacturer’s test

• The colour of the car

• The current in the heating element

• The mass of the ice

• The size of the car

• The time taken for the ice to melt