Unit 1

Question 1

What is the kinetic particle model of matter

Answer 1

All matter is made up of tiny particles which are constantly moving

Question 2

Thermal energy

Answer 2

Thermal energy is the total kinetic energy in an object

Question 3

Temperature

Answer 3

Temperature is the average kinetic energy of the atoms making up an object

Question 4

Kinetic energy

Answer 4

Kinetic energy is the energy of moving particles.

Question 5

Heat

Answer 5

Heat is the transfer of kinetic energy between two systems of different temperatures.

Question 6

Internal energy

Answer 6

Internal energy is the total energy in a system (both kinetic AND potential energy in a system)

Question 7

Conduction

Answer 7

Conduction is the heat transfer between objects which are touching each other.

Question 8

Convection

Answer 8

Convection is the heat transfer via fluids within a system

Question 9

Radiation

Answer 9

Radiation is the transfer of heat between objects that aren’t directly touching (through EM waves).

Question 10

What is a change in temperature due to?

Answer 10

The addition or removal of energy from a system.

Question 11

Specific heat capacity

Answer 11

Specific heat capacity is the amount of energy required to increase 1kg of a substance by 1 degree Celsius.

Question 12

Proportionality

Answer 12

the quality of corresponding in size or amount to something else.

Question 13

Why does the temperature of a system remain the same during a state change?

Answer 13

During a phase change, the internal energy of the substance will change, however, the temperature is not changing because all of the added energy is going towards changing the bonds between particles.

Question 14

Specific latent heat

Answer 14

Specific latent heat is the energy necessary to change the state of 1kg of a substance without changing the temperature.

Question 15

What will energy transfers and transformations in mechanical systems result in?

Answer 15

Heat loss to the environment, so the amount of useable energy is reduced

Question 16

Define efficiency

Answer 16

The ratio of useful work to the energy expended

Question 17

What is the nuclear model of the atom

Answer 17

The nuclear model of the atom is characterised by a small nucleus surrounded by electrons

Question 18

why do protons in the nucleus repel each other

Answer 18

The protons in the nucleus have a positive charge, meaning they repel one another

Question 19

Define strong nuclear force

Answer 19

The strong nuclear force is a force that attracts protons and neutrons very close to one another, keeping them close together and overwhelming the repulsive forces between protons.

Question 20

Explain the stability of a nuclide

Answer 20

The strong nuclear force acts only when protons and neutrons are close together, keeping them together and overwhelming the repulsive forces between protons as a result of electrostatic repulsion. thus, it is important to have a similar number of protons and neutrons to have a stable nucleus

Question 21

Explain natural radioactive decay

Answer 21

natural radioactive decay occurs when the nucleus is unstable. the nucleus will often decay into smaller daughter nuclei and sometimes release a form of radiation

Question 22

4 types of radiation that can occur

Answer 22

alpha decay, positive beta decay, negative beta decay, gamma decay

Question 23

describe alpha decay

Answer 23

-nucleus will emit an alpha particle
- particle made of two protons and two neutrons bound together
-positive charge
-atomic weight of 4 amu
- slow and heavy
- can be stopped by a sheet of paper

Question 24

describe beta positive decay

Answer 24

• nucleus emits a beta particle
• occurs when a proton in a nucleus spontaneously becomes a neutron
• positron and a neutrino emitted
• requires a sheet of aluminium to stop them

Question 25

describe beta negative decay

Answer 25

• too many neutrons
• nucleus emits a beta particle
  -occurs when an electron is emitted from the nucleus when a neutron spontaneously becomes a proton, an electron and an anti neutrino
• requires a sheet of aluminium to stop them

Question 26

describe gamma decay

Answer 26

• occurs when electromagnetic radiation is released from a decaying nucleus
• releases a gamma ray which travels at the speed of light
• neutrally charged
• atomic mass of 0
• it takes a slab of concrete to stop a gamma ray

Question 27

define half life

Answer 27

half life is the time taken for half of a radioisotope to decay