particle model of matter topic 3

Question 1

gas to liquid?

Answer 1

condensation

Question 2

liquid to gas?

Answer 2

evaporation

Question 3

gas to solid?

Answer 3

deposition

Question 4

solid to gas?

Answer 4

sublimation

Question 5

liquid to solid?

Answer 5

freezing

Question 6

solid to liquid?

Answer 6

melting

Question 7

describe the process of melting?

Answer 7

energy is transferred to the substance, weakening the bonds and allowing them to move more

Question 8

describe the process of boiling?

Answer 8

lots of energy is transferred to the substance, breaking the bonds

Question 9

describe freezing?

Answer 9

the particles begin to decrease their kinetic energy allowing bonds to form, energy is released to the surroundings

Question 10

describe condensing?

Answer 10

kinetic energy is decreased, allowing the particles to come closer, and stronger bonds to form

Question 11

what does the solid/liquid/gas graph show?

Answer 11

you cannot change the state AND temperature at the same time, only one or the other

Question 12

in melting and boiling, what happens?

Answer 12

• bonds are broken between particles
• internal energy increases
• temperature is constant because the energy is being used to break intermolecular forces

Question 13

doing work on a gas, results in what?

Answer 13

doing work on a gas increases internal energy so the temperature increases, e.g. using a bicycle pump

Question 14

arrangement of particles in a solid?

Answer 14

• packed in a regular structure. strong forces are held in place so can’t move. difficult to change shape

Question 15

arrangement of particles in a liquid?

Answer 15

• close together, forces keep contact but can move about
• can change shape but difficult to compress

Question 16

arrangement of particles in a gas?

Answer 16

• separated by large distances. weak forces are constantly randomly moving
• can expand to fill a space, easy to compress

Question 17

what happens to the internal energy when a substance is heated?

Answer 17

when a substance is heated, the internal energy increases. this increases temperature OR changes state

Question 18

how are gas particles moving?

Answer 18

gas particles are constantly moving in random directions

Question 19

what causes gas pressure?

Answer 19

gas pressure is caused by particles colliding with a surface and exerting a force on it

Question 20

what does increasing the temperature of a gas result in?

Answer 20

increasing the temperature of a gas, increases the average kinetic energy of the gas particles

Question 21

what happens to pressure at a constant volume and temperature?

Answer 21

at a constant volume, if temperature increases - pressure increases

Question 22

at a constant temperature, what happens if volume increases?

Answer 22

at a constant temperature, if volume increases - pressure decreases

Question 23

specific latent heat meaning?

Answer 23

the energy needed to change the state of 1kg of substance

Question 24

specific latent heat of fusion?

Answer 24

the energy needed to change the state of 1kg of substance from solid into liquid

Question 25

specific latent heat of vaporisation?

Answer 25

the energy needed to change the state of 1kg of substance from liquid into gas

Question 26

internal energy?

Answer 26

the total kinetic energy and potential energy stored by the particles that make up a system

Question 27

units of density?

Answer 27

kg/m³

Question 28

units of mass?

Answer 28

kg

Question 29

units of volume?

Answer 29

m³

Question 30

units of energy?

Answer 30

Joules (J)

Question 31

units of pressure?

Answer 31

(Pascals) Pa

Question 32

specific latent heat capacity units?

Answer 32

J/kg’c

Question 33

why does pressure increase when you heat a gas?

Answer 33

the kinetic energy of the particles increases so they hit the sides with more force and more frequently

Question 34

what happens to the temp if a substance is heated?

Answer 34

if temp rises, the kinetic energy of its particles increase

Question 35

what happens if a substance melts or boils?

Answer 35

if a substance melts or boils, the potential energy of its particles increase

Question 36

flat line in graph shows?

Answer 36

melting and boiling point of the substance

Question 37

how to calculate the density of a regularly shaped object?

Answer 37

1. use a ruler to measure length, width and height of the regularly shaped object. record this
2. calculate the volume using the formula volume = length x width x height. record this
3. using a balancing scale, measure the mass of the object
4. calculate the density using the formula density = mass/volume
5. repeat for two more regularly shaped objects

Question 38

how to calculate the density of an irregularly shaped object?

Answer 38

1. fill a measuring cylinder, with 50cm(3) of water. record the exact volume
   2. take a small portion of modelling clay, and squeeze it into any shape that fits into the measuring cylinder
   3. measure the modelling clay using a ruler, and use a balancing scale to measure the mass of the modelling clay. record this
   4. carefully, slide the modelling clay into the measuring cylinder of water by tilting the measuring cylinder at an angle. ensure the modelling clay is completely covered with the water in the beaker
2. look at the measuring beaker and calculate the change in the volume of water. you should note down the new volume of water and subtract this from the original volume of water. this will give you the volume of the modelling clay shape.
3. calculate the density of the modelling clay by using the formula density= mass/ volume, note this down.
4. calculate a mean value for the density of the modelling clay