particles and matter (paper 1)

Question 1

what is density

Answer 1

a measure of how much mass occupies a given volume

Question 2

volume of a cylinder equation

Answer 2

pi x radius squared x height

Question 3

volume of a sphere equation

Answer 3

4
— x pi x radius cubed
3

Question 4

what are the particles in a solid like

Answer 4

particles vibrate about a fixed point

close together

regular lattice

held together by strong forces of attraction

Question 5

what are the particles in a liquid like

Answer 5

able to move over eachother

held together by weaker forces of attraction

irregular pattern

Question 6

what are particles in a gas like

Answer 6

free to move in a random motion

spread far apart

no forces of attraction

move with a range of speeds

fill a volume

Question 7

what is going from a solid to a gas or going from a gas to a solid called

Answer 7

sublimation

Question 8

what is going from a gas to a liquid called

Answer 8

condensing

Question 9

what is going from a liquid to a gas called

Answer 9

evaporation

Question 10

why is it easy to compress a gas but not a solid

Answer 10

the particles in a gas are spread out

solid has no room between particles

solid has strong intermolecular forces

gases have no forces of attraction

Question 11

how can substances change state

Answer 11

by either transferring more energy to them (heating) or by transferring heat energy away (cooling)

Question 12

what is a pure substance

Answer 12

a substance that contains only one type of atom/molecule

Question 13

what do impurities in a substance effect

Answer 13

the melting, boiling and freezing points of a substance
eg. adding salt mixed with water will increase the boiling point

Question 14

what is internal energy

Answer 14

the energy stored by the particles of a substance

Question 15

what is the internal energy of a substance the sum of

Answer 15

the kinetic energy the particles have

and the elastic potential energy due to the bonds between particles

Question 16

what is latent heat

Answer 16

the energy required to change the state of 1kg if a substance without changing temperature

Question 17

specific latent heat equation

Answer 17

energy
———-
mass

Question 18

what is pressure

Answer 18

when a continuous force is exerted onto a surface. Therefore pressure can be thought of as a force per unit area

Question 19

what is Boyles Law

Answer 19

pressure decreases when volume increases

Question 20

equation for Boyles law

Answer 20

pressure x volume = constant

Question 21

1. john dalton discoveries

Answer 21

thought atoms are tiny spheres

atoms make up everything

atoms can’t be broken down any smaller

Question 22

2. JJ Thompson discoveries

Answer 22

discovered the electron

created the plum pudding model

John Daltons model could no longer be used

Question 23

features of the plum pudding model

Answer 23

ball of positive charge

negative electrons embedded inside

mass is spread throughout the atom

the charge is spread throughout the atom

Question 24

3. Ernest Rutherford discoveries

Answer 24

alpha particle scattering experiment

alpha particles were fired at thin gold foil , three observations were made which lead to three conclusions

Question 25

alpha particle scattering experiment observations and conclusions

Answer 25

most of the particles go straight through the gold foil - most of the atom is empty space

some were deflected through a big angle - the nucleus has a large positive charge

only a very small number rebounded backwards - the nucleus of the atom is very small

Question 26

4. Niels Bohr discovery

Answer 26

theorises that electrons orbit the nucleus at certain distances and with a specific amount of energy (shells)

electrons can move through the absorption and emission of radiation by the electrons