Paper 1 - Topic 3, Particle Model Of Matter

Question 1

What are chemical changes

Answer 1

Changes to the structure of a substance, the substance does not usually restore its original properties when the changes are reveresed

Question 2

What is condensation

Answer 2

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

Question 3

What is density

Answer 3

The mass per unit volume of an object

Question 4

What is evaporation

Answer 4

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

Question 5

What is freezing

Answer 5

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

Question 6

What is the temperature of gas directly proportional to

Answer 6

The average kinetic energy of its molecules

Question 7

What is internal energy

Answer 7

The energy stored by the atoms and molecules that make up a system, it is equal to the same of the total kinetic and potential energies of the particles in the system

Question 8

What is latent heat

Answer 8

The energy required for a substance to change state

Question 9

What is melting

Answer 9

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

Question 10

What is the unit for pressure

Answer 10

Pascals

Question 11

What are physical changes

Answer 11

Changes to the physical properties of a substance which can be reversed, changes of state are physical changes as they can restore their original properties

Question 12

What is pressure

Answer 12

The force acting perpendicular to a surface

Question 13

What is specific heat capacity

Answer 13

The amount of energy needed to heat 1kg of a substance by 1 degrees Celsius

Question 14

What is sublimation

Answer 14

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

Question 15

Describe gases

Answer 15

• most kinetic energy
• particles can move freely
• lowest density

Question 16

Describe solids

Answer 16

• particles can only vibrate in fixed places
• highest density
• least amount of kinetic energy

Question 17

Describe liquids

Answer 17

The particles can flow over each other and the particles are close together with an irregular arrangement

Question 18

What always stays the same in changes of state

Answer 18

The mass

Question 19

What does temperature increase depend on in specific heat capacity

Answer 19

• material type
• material mass
• energy inputted

Question 20

What happens when work is done on a gas

Answer 20

Energy is transferred to it

Question 21

What is temperature determined by in particles

Answer 21

The amount of kinetic energy of the substance, the higher the temperature, the higher the kinetic energy

Question 22

What does density depend on

Answer 22

The spacing of the atoms in matter

Question 23

What happens when you heat a system

Answer 23

• heating increases the energy the particles have
• this increases internal energy
• this either raises the temperature of the system or produces a change in state

Question 24

How does changing the volume of a gas affect the pressure

Answer 24

Increasing the volume in which a gas is contained (at a constant temp) can lead to a decrease in pressure this is due to the reduced number of collisions per unit area

Question 25

What does doing work on a gas mean

Answer 25

Compressing or expanding the gas, changing the volume

Question 26

What happens when you add more particles into a fixed volume

Answer 26

• more particles are present so more collisions occur per unit time with the walls so pressure increases
• energy is transferred to the particles when more gas is added into the fixed volume so this heats the gas

Question 27

What happens when a fixed number of particles are in a smaller volume

Answer 27

• particles collide with the wall
• particles gain momentum as the rebound velocity is greater than the approaching velocity
• as the particles have a greater velocity the pressure increases as the particles collide with the walls more frequently