P6 particles

Question 1

what are the properties of particles in a solid? (how are they arranged)

Answer 1

particles are very close together
arranged in a regular pattern
particles vibrate but do not move

Question 2

what is the arrangement of particles in a liquid?

Answer 2

particles are close together
not arranged in a regular pattern
particles can move around each other

Question 3

what is the arrangement of particles in a gas?

Answer 3

particles are very far apart
not arranged in any pattern
moving very rapidly

Question 4

what is density?

Answer 4

the mass of an object for a given volume

Question 5

what is the formula which links density mass and volume?

Answer 5

density = mass / volume

Question 6

what is the density pattern for solids?

Answer 6

they usually have a very high density
the particles are packed closely together so they have a lot of mass for their volume

Question 7

what is the density pattern for liquids?

Answer 7

they are usually high density
the particles are close together so they have a lot of mass for their volume

Question 8

what is the density pattern for gases?

Answer 8

they have a low density
the particles are far apart so gases have a small mass for their volume

Question 9

what is the difference between a regular and an irregularly shaped object?

Answer 9

regular objects have dimensions which are easy to measure
irregular objects have dimensions which cannot be easily measured

Question 10

how can the mass of an object be determined?

Answer 10

using a balance

Question 11

how do you work out the volume of a regularly shaped object?

Answer 11

measure the length width and depth
multiply them together

Question 12

how do you determine the volume of an irregularly shaped object?

Answer 12

fill a eureka can with water up to the spout
place the object into the can. this causes the water to be displaced and flow out of the spout
measure the volume of water displaced. this is equal to the volume of the object

Question 13

what gives particles potential energy?

Answer 13

intermolecular forces and chemical bonds

Question 14

what is internal energy of particles?

Answer 14

the energy stored in a system by particles
it includes the total kinetic and potential energy of all the particles that make up a system

Question 15

what happens when you heat particles?

Answer 15

their internal energy store increases.
this can cause them to change state

Question 16

what happens when you cool particles?

Answer 16

the amount of internal energy decreases
this can cause them to change state

Question 17

what is sublimation?

Answer 17

when a solid turns directly to a gas

Question 18

what happens to mass when changes of state take place?

Answer 18

mass is always conserved. particles are not added or taken away

Question 19

what type of change is a change of state?

Answer 19

a physical change not a chemical one
if the change is reversed, the material recovers its original properties

Question 20

what is evaporation?

Answer 20

when a liquid turns to a gas but only on the surface of the liquid
only particles on the surface have enough energy to change to a gas

Question 21

what is specific heat capacity?

Answer 21

the amount of energy needed to raise the temperature of 1 kg of a substance by 1 degree

Question 22

what does it mean if a material stores a lot of energy?

Answer 22

they need to gain lots of energy to increase the temperature and transfer lots of energy when they cool down

Question 23

what is happening when the line is horizontal on a heating/cooling graph?

Answer 23

the substance is changing state
the energy is being used to weaken or break the forces of attraction between the particles

Question 24

what happens when a substance changes state?

Answer 24

energy is being put into the substance when it is being heated up. this breaks the forces of attraction between the molecules allowing the substance to chance state

Question 25

what is the specific latent heat of a substance?

Answer 25

the amount of energy needed to change the state of 1 kilogram of the substance with no change in temperature

Question 26

what is the difference between specific latent heat of fusion and vaporisation?

Answer 26

fusion is from solid to liquid
vaporisation is from liquid to a vapour
both are with no temperature change

Question 27

what is the pressure of a gas due to?

Answer 27

the particles colliding at an right angle with the walls of the container the gas is held in

Question 28

how can the pressure of a gas be increased?

Answer 28

increase the number of collisions per second
or
increase the energy of each collision

Question 29

what are the characteristics of gases at low temperatures?

Answer 29

particles have a lower kinetic energy. there are fewer collisions per second and these collisions are lower energy
this means the pressure is low

Question 30

what are the characteristics of gases at high temperatures?

Answer 30

particles have higher kinetic energy
there are more collisions per second with higher energy
this means the pressure is high

Question 31

why does increasing the volume of the container a gas in decrease the pressure?

Answer 31

the spacing is increased between the particles
particles now travel much further before colliding with the walls of the container
this reduces the number of collisions per second, reducing the pressure

Question 32

how is the volume of the gas related to the pressure?

Answer 32

they are inversely proportional
if the volume increases, the pressure decreases

Question 33

what does the equation pV = constant mean?

Answer 33

because the pressure is multiplied by the volume is constant, if the pressure is increased, then the volume is decreased by the inverse amount

Question 34

what is work?

Answer 34

the transfer of energy by a force

Question 35

what happens when work is done on a gas?

Answer 35

energy is transferred to the gas particles
this means the internal energy of the particles is increased
because the average kinetic energy of the particles (internal energy = kinetic and potential) has increased, the average temperature increases