Particle Model Of Matter

Question 1

Density

Answer 1

How closely packed the particles are in a solid, liquid, or gas

The amount of mass per unit volume

Question 2

Density formula

Answer 2

Mass / volume

m / V

Question 3

Density of irregular shaped object practical

Answer 3

Measure the mass of the stone

Fill the displacement can until the water is level with the bottom of the pipe

Place a measuring cylinder under the pipe ready to collect the displaced water

Carefully drop the stone into the can and wait until no more water runs into the cylinder

Measure the volume of the displaced can

Question 4

Density of water practical

Answer 4

Measure the mass of the measuring cylinder

Pour 50 cm3 of water into the measuring cylinder and measure its new mass

Subtract the mass in step 1 from the mass in step 2

Question 5

Solid properties

Answer 5

Regular pattern

Fixed position

Vibrate on the spot

Keep their shape

Question 6

Liquid properties

Answer 6

Random arrangement

Close together

Move around

Takes the shape of a container

Question 7

Gas properties

Answer 7

Random arrangement

Far apart

Move in all directions

Fill the shape of the container

Question 8

Kinetic theory of matter - solids

Answer 8

Particles in a solid are held together by strong forces of attraction and vibrate at their position

At low temperatures, the vibration is small and can be considered fixed

When a solid gains energy the particles vibrate more and cause
the neighbouring particles to vibrate also

Question 9

Kinetic theory of matter - liquids

Answer 9

The intermolecular forces within a liquid are too weak to keep particles in a fixed position so they are free to move

They move randomly and so
therefore liquids flow

Question 10

Kinetic theory of matter - gases

Answer 10

The particles in a gas are in constant random motion as there are very weak forces between them

The particles are spaced further apart than in liquids

Question 11

Evaporation

Answer 11

When particles at the surface of a liquid gain enough energy to leave as a gas

Question 12

Factors increasing the rate of evaporation

Answer 12

Increasing the surface area of the liquid

Increasing the temperature of the liquid

Question 13

Condensation

Answer 13

The H2O molecules in the air hit a cold surface and therefore condense, changing state from gas to a liquid

Question 14

Factors increasing the rate of condensation

Answer 14

Increasing the surface area

Reducing surface temperature

Question 15

Sublimation

Answer 15

The process by which a solid directly changes to a gaseous state (missing the liquid state).

E.g. dry ice

Question 16

Internal energy

Answer 16

The total amount of kinetic and chemical potential energy of all particles in a system

Question 17

Increasing internal energy

Answer 17

Heating a substance will increase its kinetic energy store, and therefore an internal energy change

A change in state causes an increase in potential energy, and therefore an increase in internal energy change

Question 18

Specific heat capacity

Answer 18

The quantity of energy needed to raise the temperature of a 1kg object by 1°C

Question 19

Specific heat capacity formula

Answer 19

Change in thermal energy / mass x temperature change

ΔJ / m x ΔT

M = mass (kilogram, kg)

ΔJ = change in thermal energy (joules, J)

ΔT = temperature change (celsius, °C)

Question 20

Specific latent heat

Answer 20

The amount of energy required to change the state of 1 kilogram of a substance without changing its temperature

Question 21

Specific latent heat of fusion

Answer 21

Energy needed to change 1kg of a substance from a solid state to a liquid state

Question 22

Specific latent heat of fusion formula

Answer 22

Energy = mass x specific latent heat of fusion

E = m x Lf

Question 23

Specific latent heat of vaporisation

Answer 23

Energy needed to change 1kg of a
substance from liquid state to gaseous state

Question 24

Specific latent heat of vaporisation formula

Answer 24

Energy = mass x specific latent heat of vaporisation

E = m x Lv

Question 25

Pressure

Answer 25

Force / area

F / A

Question 26

Factors increasing pressure

Answer 26

As temperature increases pressure increases as;

the average kinetic energy of the molecules increases and therefore the molecules hit the sides of the container more often, increasing the force exerted = more pressure

Question 27

Boyle’s law

Answer 27

States that for a fixed amount of (ideal) gas at a fixed temperature pressure is inversely proportional to the volume