P6 - Molecules And 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

Solid properties

Answer 3

Regular pattern

Fixed position

Vibrate on the spot

Keep their shape

Question 4

Liquid properties

Answer 4

Random arrangement

Close together

Move around

Takes the shape of a container

Question 5

Gas properties

Answer 5

Random arrangement

Far apart

Move in all directions

Fill the shape of the container

Question 6

Kinetic theory of matter - solids

Answer 6

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 neighboring particles to vibrate also.

Question 7

Kinetic theory of matter - liquids

Answer 7

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 8

Kinetic theory of matter - gases

Answer 8

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 9

Evaporation

Answer 9

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

Question 10

Factors increasing the rate of evaporation

Answer 10

Increasing the surface area of the liquid

Increasing the temperature of the liquid

Question 11

Condensation

Answer 11

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

Question 12

Factors increasing the rate of condensation

Answer 12

Increasing the surface area

Reducing surface temperature

Question 13

Sublimation

Answer 13

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

E.g. dry ice

Question 14

Internal energy

Answer 14

The combined energy of the kinetic and potential energy of the
particles in the substance

Question 15

Increasing internal energy

Answer 15

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 internal energy change

Question 16

Specific latent heat

Answer 16

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

Question 17

Specific latent heat of fusion

Answer 17

Refers to the energy supplied to change 1kg of a substance from a solid state to a liquid state.

Question 18

Specific latent heat of fusion formula

Answer 18

Energy = mass x specific latent heat of fusion

E = m x Lf

Question 19

Specific latent heat of vaporisation

Answer 19

Refers to the energy supplied to change 1kg of a
substance from liquid state to gaseous state

Question 20

Specific latent heat of vaporisation formula

Answer 20

Energy = mass x specific latent heat of vaporisation

E = m x Lv

Question 21

Pressure

Answer 21

Refers to when a continuous force is exerted onto a surface

Measured in pascals

Question 22

Pressure formula

Answer 22

Force / area

F / A

Question 23

Factors increasing pressure

Answer 23

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 24

Boyle’s law

Answer 24

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