P6 molecules and matter (paper 1)

Question 1

define the term density

Answer 1

the amount of mass in a certain volume

Question 2

what is the equation for density

Answer 2

density (kg/m^3) = mass (kg or g) / volume (m^3 or cm^3)

Question 3

what is the equation for volume

Answer 3

height x width x depth

Question 4

what are changes of state caused by

Answer 4

heating or cooling the substance - in the case of heating this allows the particles to break the bond holding them together

Question 5

describe the shape of a solid

Answer 5

fixed

Question 6

describe the shape of a liquid and a gas

Answer 6

fills container

Question 7

describe the volume of a solid or liquid

Answer 7

fixed

Question 8

describe the volume of a gas

Answer 8

can be changed

Question 9

which state has the highest density

Answer 9

solids

Question 10

which state has the lowest density

Answer 10

gases

Question 11

what does the density of an object depend on

Answer 11

• what its made of
• how its particles are arranged

Question 12

describe the particles in a dense material

Answer 12

tightly packed together

Question 13

if you compress a material what happens to its density

Answer 13

it gets more dense

Question 14

why do materials get more dense after being compressed

Answer 14

• the mass doesnt change
• BUT the volume decreases

Question 15

can you compress a solid

Answer 15

no

Question 16

can you compress a liquid

Answer 16

no

Question 17

why cant you compress a liquid

Answer 17

although particles are not fixed in position, they are still touching close together

Question 18

describe the method to find the density of a solid object

Answer 18

• use a balance to measure its mass
• if a regular solid measure length, width, height with a ruler and calculates volumes with v = wlh
• for an irregular solid submerge it into a eureka can filled with water
• volume of water displaced is volume of solid
• calculate density using mass/volume

Question 19

what is the name of apparatus used to measure the density of an irregular object

Answer 19

eureka can

Question 20

describe the method to find the density of a liquid

Answer 20

• place measuring cylinder on balance and zero it
• pour 10ml of liquid in and record mass
• repeat until cylinder is full and record the total volume and mass each time
• for each measurement use d=m/v for density
• calculate average of values and that is the density

Question 21

what is meant by the term ‘internal energy’

Answer 21

the energy stored by the particles making up a system

Question 22

what energy stores do particles have and explain this

Answer 22

• kinetic energy = they vibrate and move around
• potential energy = their positions

Question 23

what is the energy in a system stored by

Answer 23

its particles

Question 24

what is meant by the term ‘internal energy of a system’

Answer 24

the total energy that its particles have in their kinetic and potential energy stores

Question 25

how can you increase the internal energy of a system

Answer 25

heat it

Question 26

why does heating a system increase the internal energy of it

Answer 26

particles gain energy in their kinetic stores and move faster

Question 27

what does increase in internal energy lead to

Answer 27

- change in temperature - change in state

Question 28

if a temperature change occur what does the size of this change depend on

Answer 28

- mass of substance - what its made of (specific heat capacity) - the energy input

Question 29

when does a change in state occur

Answer 29

when the particles are heated enough that they have enough energy in their kinetic stores to break the bonds holding them together

Question 30

when bonds form (cool) what happens to the energy of particles

Answer 30

particles loose energy

Question 31

what is the law when a substance changes state

Answer 31

mass is conserved

Question 32

what is meant by the term 'latent heat'

Answer 32

the energy needed for 1kg of substance to change its state without changing temperature

Question 33

what set value for a substance is for change in temperature

Answer 33

specific heat capacity

Question 34

what set value for a substance is used for change in state

Answer 34

latent heat

Question 35

what are the two types of latent heat

Answer 35

- latent heat of fusion - latent heat of vapourisation

Question 36

what is latent heat of fusion

Answer 36

when a substance goes from a solid to a liquid

Question 37

what is the latent heat of vapourisation

Answer 37

when a substance goes from a liquid to gas

Question 38

what is the formula for latent heat and energy input for it with mass

Answer 38

E (J) = mass (kg) x latent heat of substance (J/kg) E = mL

Question 39

what is the forumla for electrical energy

Answer 39

E (J) = current (A) x time (s) x voltage (V)

Question 40

what unit is used to measure pressure

Answer 40

Pascals (Pa)

Question 41

state Boyle's Law

Answer 41

volume is inversely proportional to pressure

Question 42

what is the formula for Boyle's law

Answer 42

- pressure x volume = constant - pressure = constant / mass

Question 43

what do colliding gas particles create...

Answer 43

pressure

Question 44

explain how gas particles collidign creates pressure

Answer 44

- they move at high speeds - when they collid with something or each other they exert a force - in a sealed container the outward gas pressure is the total force exerted by all particles in the gas area

Question 45

if gas particles are moving faster what will happen to the pressure

Answer 45

it will increase as it increases the ent force

Question 46

if temperature is constant what does increasing the volume of a gas do to its pressure

Answer 46

decrease it