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Question 1

density equation

Answer 1

mass / volume

Question 2

what is density measured in?

Answer 2

g/cm3 or kg/m3

Question 3

density practical

Answer 3

1. measure mass of object with mass balance
2. fill bottle with liquid of a known density e.g water
3. place object into density bottle, repeat, whilst putting a stopper into bottle and drying inside, measuring mass of bottle
4. calculate volume of displaced water
   volume = mass / density

Question 4

solid

Answer 4

strong forces of attraction, fixed arrangement of particles. don’t contain much energy in kinetic energy stores: can only vibrate

Question 5

liquid

Answer 5

weaker forces of attraction than solids particles closed but can move over each other/form irregular arrangements. more energy in kinetic energy stored: move in random directions at low speeds

Question 6

gas

Answer 6

almost no forces of attraction between particles. more energy than solids + liquids in kinetic energy store: free to move in random directions at different speeds

Question 7

what happens to internal energy during change of state?

Answer 7

spacing between particles changes
when a liquid is heated: extra energy transferred into particle’s kinetic energy store makes them move faster
when a solid is heated: particles vibrate faster until forces are partly overcome/begin to move/boil.

Question 8

internal thermal energy: boiling

Answer 8

when particles have enough energy to overcome attraction to each other, gas will form in liquid (boiling)

Question 9

mass + change of state

Answer 9

in a closed system, mass isn’t affected by change of state as particles aren’t changing, just being rearranged.

Question 10

density + change of state

Answer 10

volume changes as particle density changes (e.g liquid to gas). due to this, density changes. substances are most dense as solids, least dense as gas (due to particle arrangement)

Question 11

specific heat capacity definition

Answer 11

change in energy in a substances thermal store needed to raise the temperature of 1kg of the substance by 1 degree C.

Question 12

specific heat capacity

Answer 12

temperature measures average internal energy of a substance. some materials take longer than others to heat up. materials store a lot of energy for a given change in temp, release lots to cool down.

Question 13

water: specific heat capacity

Answer 13

4200J/kg degrees celsius

Question 14

specific heat capacity unit

Answer 14

J/Kg degrees C

Question 15

change in thermal energy equation

Answer 15

mass x specific heat capacity x temperature change

Question 16

specific heat capacity practical

Answer 16

(use a thermally insulated container to reduce energy wasted to surroundings)
1. measure mass of container using a mass balance
2. fill container with water + measure again (difference in mass = mass of water)
3. measure temp of water, turn on power.
4. watch thermometer, stop at certain points (e.g every 10 degrees and measure energy in joulmeter + increase in temp)
5. calculate specific heat capacity
6. repeat 3x
(a voltmeter and ammeter could be used instead, by timing how long heater was on/energy supplied).
5

Question 17

specific latent heat

Answer 17

when a substance is melting/boiling energy is used to break bonds between particles
when a substance is condensing/freezing, bonds are formed between particles which release energy (meaning temp doesn’t decrease during change of state)
different between different materials/changes of states.

Question 18

specific latent heat practical

Answer 18

1. fill a beaker with crushed ice
2. place a thermometer into beaker and record temp
3. using bunsen, heat gradually
4. every 20 seconds record temp/state of ice until water begins to boil
5. plot graph of temp against time

Question 19

specific latent heat definition

Answer 19

energy needed to change state of 1kg of a substance (without changing temp)

Question 20

thermal energy equation

Answer 20

mass (kg) x specific latent heat (J/kg)

Question 21

specific latent heat/changes of state

Answer 21

melting/freezing: specific latent heat of fusion
evaporating/boiling/condensing: specific latent heat of vaporisation

Question 22

particle motion in gases

Answer 22

collision between gas particles exert a forced due to them having a mass: creating a net force acting outwards on the inside surface of their container (creating pressure)
more particles in a given volume = more collisions = more pressure

Question 23

increasing temp inside pressure

Answer 23

pressure a gas exerts depends on speed of particles/number of collisions
a gas held in a container with a fixed mass/volume will transfer its energy to kinetic energy stores of gas particles.
move faster when heated

Question 24

decreasing temp inside pressure

Answer 24

when cooled particles have less energy/move less quickly, therefore there is less pressure as there will be less collisions/force

Question 25

absolute zero

Answer 25

coldest temp anything can get -273 degrees celsius particles have little energy in their kinetic energy stores as possible: essentially still

Question 26

what are kelvins?

Answer 26

temperature scale begging at absolute zero celsius to kelvins: + 273 kelvins to celsius: -273

Question 27

force and elasticity

Answer 27

applying force: stretch, compress, bend to change more than one shape force needs to be acting on an object, otherwise it will just change direction

Question 28

elastic objects

Answer 28

elastic objects are elastically distorted if it goes back to it’s original shape/length when the force is removed all energy is transferred to elastic potential energy store

Question 29

inelastic objects

Answer 29

inelastic objects are inelastically distorted if it doesn’t return to it’s original shape/length when force is removed

Question 30

elastic limit

Answer 30

when an object stops distorting elastically and begins to distort inelastically

Question 31

work done: elasticity

Answer 31

work is done when a forces stretches/compresses an object + causes energy to be transferred to the elastic potential energy store of the object.

Question 32

extension is directly proportional to force

Answer 32

applied force = spring constant x extension (m) spring constant depends on material being stretched (e.g more stiff material will have a stronger spring constant) linear relationship -> this direct proportionality is limited (elastic limit)

Question 33

graph of extension/force proportionality

Answer 33

when maximum force is reached, graph begins to curve, becomes non-linear (limit of proportionality) elastic limit: where the object becomes permanently stretched.

Question 34

investigating elasticity: practical

Answer 34

1. add mass to spring, allow spring to come to rest 2. record new length of spring: extension = change in length 3. repeat, adding masses 4. plot a graph of results

Question 35

investing elasticity results

Answer 35

more work needed to be done to cause a larger extension, force doing work is gravitational force. work done is calculated by working out it area underneath straight line (up until value of force) as long as spring isn’t stretched passed limit of proportionality, work done to spring = energy stored in elastic potential energy store

Question 36

energy transferred in stretching equation

Answer 36

1/2 x spring constant (N/m) x extension squared (m2)