Topic 3 – Particle Model of Matter Fundimentals

Question 1

what does the density tell you

Answer 1

the mass for a given volume

Question 2

whats the equation for density?

Answer 2

density = mass / volume

Question 3

whats the unit of density?

Answer 3

kg/m ^3

Question 4

whys polystyrene solid but has low density?

Answer 4

v open structure and is full of air spaces , it has a small mass for its volume

Question 5

how to find density of a regular object?

Answer 5

1/ determine the mass using a balance
2/ measure length of each side using a ruler to find volume
3/ put into equation

Question 6

how to find density of an irregular object

Answer 6

1/ find mass using balance
2/ fill eureka can w water and put measuring cylinder by spout. place object into water and see how much water was displaced.
3/measure waters volume

Question 7

what is potential energy

Answer 7

intermolecular forces and chemical bonds

Question 8

what is the internal energy

Answer 8

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

Question 9

what happens when you heat a solid (in terms of internal energy)

Answer 9

internal energy increases

Question 10

solid directly to a gas is called what?

Answer 10

sublimation

Question 11

what is evaporation

Answer 11

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

Question 12

what is the specific heat capacity

Answer 12

the amount of energy required to raise the temp of 1kg of a substance by 1 degree C

Question 13

In a heating and cooling graph, when is change in state happening?

Answer 13

when the temp stops rising and line becomes horizontal

Question 14

what happens to particles when theyre changing state?

Answer 14

energy being put in is weakening/ breaking the forces of attraction between them, allowing a change of state

Question 15

what is increasing and staying the same during a change of state?

Answer 15

internal energy store is increasing but temperature does NOT increase

Question 16

what is specific latent heat

Answer 16

the amount of energy required to change the state of 1kg of the substance with NO change in temperature

Question 17

what is the specific latent heat of FUSION?

Answer 17

the energy required to change 1kg of a substance from a solid to liquid with no change in temp

Question 18

what is the specific latent heat of VAPORISATION?

Answer 18

The energy required to change 1kg of a substance from a liquid to a vapour with no change in temperature

Question 19

whats the pressure of a gas due to?

Answer 19

particles colliding with the walls of the container that the gas is held in. The particle collisions cause a force which act at right angles to the walls of the container. This force acting over areas of the container causes pressure.

Question 20

how to increase the pressure of a gas?

Answer 20

increase the number of collisions per second OR the energy of each collision
(eg increase temp of gas)

Question 21

whys lower temp of gas a lower pressure?

Answer 21

At low temperatures, particles have lower kinetic energy so there are fewer collisions per second. These are lower energy collisions

Question 22

What happens if you take the same gas and increase of the volume of the container (w/ constant pressure)

Answer 22

pressure is reduced because there’s increased spacing between particles, they now travel much further before colliding with walls of the container, this reduces n.o of collisions per second between particles and the walls of the container

Question 23

the pressure of gas is ______ to the volume meaning….

Answer 23

inversely proportional

if volume increases, pressure decreases

Question 24

whats the equation for the constant?

Answer 24

pressure (Pa) x Volume = constant

Question 25

because pressure multiplied by the volume is a constant, if we double the pressure we _____ the volume

Answer 25

halve

Question 26

if you compress the gas by applying a force on the piston, its an example of what?

Answer 26

work done on the gas

Question 27

what is work defined as

Answer 27

the transfer of energy by a force

Question 28

what does is mean to have transferred energy by force?

Answer 28

the internal energy of the gas increases. And due to kinetic energy increasing, temp increases.

Question 29

why can bicycle pumps get warm (sans)

Answer 29

because work is being done, increasing the internal energy