particle model of matter

Question 1

what is density

Answer 1

measure of compactness of a substance

Question 2

calc for density

Answer 2

mass / volume

Question 3

describe solids

Answer 3

strong force of attraction, particles in fixed positions, have little energy so vibrate, have the highest density

Question 4

describe liquids

Answer 4

weaker force of attraction so particles are close but move past each other, more energy than solids, less dense than solids

Question 5

describe gas

Answer 5

no force of attraction, particles have the most energy, less dense than liquids

Question 6

what is internal energy

Answer 6

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

Question 7

what do the particles contain in a closed system

Answer 7

kinetic energy stores and potential energy stores

Question 8

how do you increase the internal energy

Answer 8

heating transfers energy increasing internal energy

leads to change in temp or change in state

Question 9

what happens if a substance is heated anougth

Answer 9

the particles will have enough energy in kinetic energy stores to break bonds

Question 10

what is a change of state

Answer 10

a physical change

same number of particles just arranged differently

Question 11

what happens to the internal energy when you melt or boil

Answer 11

increase internal energy but is used for breaking intermolecular bonds

Question 12

what happens to the internal energy when you condense or frezze

Answer 12

bonds form which releases energy so internal energy decreases

Question 13

what is specifc latent heat

Answer 13

amount of energy needed to change 1kg of it from one state to another without a change in temp

Question 14

calc for specific latent heat

Answer 14

slh = energy / mass

Question 15

how does temp increase speed

Answer 15

temp is related to the average energy in the kinetic energy stores so the higher the temp, higher the average energy

Question 16

how do colliding particles create pressure and how you increase it

Answer 16

when collide they exert force and so presusre

faster particles and more collisions increase the net force and so pressure,

Question 17

what increases the speed of colling particles

Answer 17

increasing temp

Question 18

how does pressure dcrease

Answer 18

if temp is constant increasing the volume means particles spread

Question 19

how does a change in pressure cause a change in volume

Answer 19

pressure of gases cause a net force outwards at right angles but there is also a force out side due to the pressure outside

change in pressure either causes container to compress or expand

Question 20

how can doing work on a gas increase temp

Answer 20

transfer energy by applying a force then you do work

doing work will increase its internal energy and transfers the energy to the kinetic energy stores increasing temp