3: Particle Model of Matter

Question 1

Change in Thermal Energy:

Answer 1

The product of the mass, specific heat capacity and
temperature change of a substance.

Question 2

Chemical Changes:

Answer 2

Changes to the chemical structure of a substance. The substance does not usually restore its original properties when the changes are reversed.

Question 3

Condensation:

Answer 3

The changing from vapour state to a liquid state, when a substance is cooled.

Question 4

Density:

Answer 4

The mass per unit volume of an object.

Question 5

Evaporation:

Answer 5

The changing from liquid state to a vapour state, when a substance is heated.

Question 6

Freezing:

Answer 6

The changing from a liquid state to a solid state, when a substance is cooled.

Question 7

Gas Temperature:

Answer 7

The temperature of a gas is directly proportional to the average kinetic energy of its molecules.

Question 8

Internal Energy:

Answer 8

The energy stored by the atoms and molecules that make up a system. It is equal to the sum of the total kinetic and potential energies of the particles in the system.

Question 9

Latent Heat:

Answer 9

The energy required for a substance to change state.

Question 10

Melting:

Answer 10

The changing from solid state to liquid state, when a substance is heated.

Question 11

Pascals:

Answer 11

The unit of pressure, equal to a force of one Newton acting perpendicular to an area of one metre squared.

Question 12

Physical Changes:

Answer 12

Changes to the physical properties of a substance which can be reversed. Changes of state are physical changes since substances can restore their original
properties when the changes are reversed.

Question 13

Pressure:

Answer 13

The force acting perpendicular to a surface, per unit area.

Question 14

Specific Heat Capacity:

Answer 14

The amount of energy needed to increase the temperature of one kilogram of a given substance by one degree Celsius.

Question 15

Specific Latent Heat of Fusion:

Answer 15

The amount of energy needed to change the state of one kilogram of a substance from solid state to liquid state, whilst held at constant temperature.

Question 16

Specific Latent Heat of Vaporisation:

Answer 16

The amount of energy needed to change the state
of one kilogram of a substance from liquid state to vapour state, whilst held at constant temperature.

Question 17

Specific Latent Heat:

Answer 17

The amount of energy needed to change the state of one kilogram of a substance, whilst held at constant temperature.

Question 18

Sublimation:

Answer 18

The direct changing of a substance from a solid state to a vapour state, without passing through the liquid phase.