particle model of matter

Question 1

what is the kinetic energy within the particles

Answer 1

all particles move which uses kinetic energy

Question 2

what is potential energy

Answer 2

it is the energy from inter molecular forces and bonds

Question 3

what is specific heat capacity

Answer 3

it is the amount of energy required to raise the temperature of 1kg of a substance by 1 degree

Question 4

what is specific latent heat

Answer 4

the specific latent heat is the amount of energy required to change the state of one kilogram of the substance with no change in the temperature

Question 5

what is latent heat of fusion

Answer 5

the energy required to change 1kg of solid to liquid with no change in temperature

Question 6

what is specific latent heat of vaporisation

Answer 6

the energy required to change 1kg of liquid to gas with no change in room temperature

Question 7

what is the formula for energy to change state

Answer 7

energy to change state (J) = mass (Kg) * specific latent heat (J/Kg)

Question 8

what is pressure

Answer 8

pressure is when gas particles exert a force on their container when colliding

Question 9

what is the relation with gas pressure and volume

Answer 9

they are inversely proportional

Question 10

what happens if an atom absorbs radiation

Answer 10

it moves an electron to a higher energy level which releases radiation when it moves back down an energy level

Question 11

what is the atomic number

Answer 11

that amount of protons in an atom

Question 12

what is radioactive decay

Answer 12

it is when an atom has an unstable nucleus so gives out radiation to become stable

Question 13

what is activity of an atom

Answer 13

activity is the rate at which the unstable nuclei decays

Question 14

what is activity measured in

Answer 14

becquerels (Bq)

Question 15

what is the count rate

Answer 15

it is the number of decays each second which can be measured using a Geiger tube

Question 16

what is a beta particle

Answer 16

it is a high speed electron fired from the nucleus at high speeds and comes from when a nucleus splits into a proton and an electron

Question 17

what is a gamma ray

Answer 17

it is a type of radiation emitted from the nucleus

Question 18

what stops each type of radiation

Answer 18

alpha - paper
beta - few millimeters of aluminium
several cm of lead
gamma - several cm of lead

Question 19

what is the half life of a substance

Answer 19

the time it takes for the amount of unstable nuclei of the isotope to half or the amount of time that it takes for the count rate to fall to half its initial level

Question 20

what is irradiation

Answer 20

exposing an object to radiation

Question 21

what are the sources of background radiation

Answer 21

• certain rocks are radioactive such as granite
• cosmic rays through space such as supernovas
• nuclear weapons
• nuclear accidents

Question 22

what is the unit for radiation

Answer 22

a sievert or millisieverts

Question 23

what are the uses of radioactivity in medicine

Answer 23

• the thyroid gland absorbs iodine so radioactive iodine can be used to check its functionality
• a radioactive tracer can be used to scan the body

Question 24

what are the limitations of radioactive tracers

Answer 24

the radiation needs to be able to be able to pass out of the body and move for a long distance in air (beta,gamma) and must not be ionising. The tracer should not decay into radioactive isotopes and must have a short half life

Question 25

describe nuclear fission

Answer 25

one electron hits an unstable nucleus such as a uranium nucleus and it splits (undergoes nuclear fission) and releases 2 daughter nuclei (roughly the same size) and 2 or 3 neutrons and gamma radiation. this is called a chain reaction

Question 26

what is nuclear fusion

Answer 26

when two light nuclei are joined to form a heavier nucleus so the mass of the nuclei can be converted to energy which is released as radiation and can only happen in stars