P3 key questions

How much mass a substance contains compared to it's volume is… density

State the equation which links density, mass and volume ρ=m/v

Name the change of state when a liquid becomes a solid freezing

Name the change of state when a solid becomes a liquid melting

Name the change of state when a liquid becomes a gas evaporation

Name the change of state when a gas becomes a liquid condensation

Name the change of state when a solid becomes a gas (without passing through liquid form) sublimation

Changes of state are caused by the amount of _________ a substance has energy

State changes are examples of ___________ change physical

Physical changes are ones which can be _____________ reversed

A change which creates new products and cannot be reversed is _________ change chemical

The energy stored inside a system by the particles which make it up is known as ____________ energy internal

What is internal energy? The total kinetic energy and potential energy of all the particles in a system

Energy stored within moving objects is __________ kinetic

Energy stored in particles because of their position is…? potential energy

Particles wich are further apart have _________ potential energy more

The energy needed to raise the temperature 1 kg of a material by 1ᵒC is the __________ specific heat capacity

The average kinetic energy of particles is known as the ___________ temperature

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

Latent heat of fusion is for changing…? solid to liquid

Latent heat of vaporisation is for changing….? liquid to vapour (gas)

Increasing temperature ______________ pressure in a gas if volume is constant increases

The force exerted by gas on a surface as the particles collide with it is known as….? gas pressure

State the units of density kg/m3

State the units of volume m3

Sketch the heating curve for water teacher to draw on board…

Draw a particle diagram for a solid teacher to draw on board…

Draw a particle diagram for a liquid teacher to draw on board…

Draw a particle diagram for a gas teacher to draw on board…

Why doesn't temperature increase during melting? Energy is being used to weaken forces between particles

Why doesn't temperature increase during evaporation Energy is being used to weaken forces between particles

Why does temperature of a substance increase as it is heated? Particles gain more kinetic energy and temperature is a measure of kinetic energy

Particles are arranged regularly in a ….? solid

Particles are arranged randomly, but touching in a …? liquid

Particles move around randomly in a ….? gas

Define atom The smallest part of an element that can exist.

All substances are made up of…? atoms

The radius of an atom is …? 0.1 nm (1 x 1010 m)

The overall charge on an atom is… zero/neutral

Define element Contains only one type of atom

Substances found in the periodic table are…? elements

Approximately how many elements are there? 100

Define isotope An atom of the same element with different numbers of neutrons

Define radioactive decay An unstable nucleus changes to become more stabe and gives out radiation

We cannot predict when a given atom will decay, this means that radioactive deacy is ….? random

Define activity Rate at which decay occurs

What are the units of activity? Becquerels (Bq)

Define count rate Number of decays recorded each second by a Geiger-Muller tube

Defne half life The time taken for number of radioactive nuclei in a sample to halve OR time taken for count rate (or activity) from a sample to fall to half its initial value

Define contamination The unwanted presence of materials containing radioactive atoms

Define irradiation When an object is exposed to radiation

Does an irradiatied object become radioactive itself? no

The process of radiation removing electrons from atoms to form ions is called…? ionisation

If ionisation happens in DNA it can cause ___________ which may result in ____________ mutations, cancer

Define peer review Checking of scientific results by other scientific experts

Define mass number The total number of protons and neutrons in an atom

Define atomic number The number of protons in an atom (number of electrons is the same in a neutral atom)

Electrons in atoms are located in ___________ energy levels

Absorption of radiation by an atom may result in ____________ moving to a ________________ energy level electrons, higher

Emission of radiation from an atom may lead to _____________ moving to a ______________ energy level electrons, lower

Who came up with the Plumb Pudding model of the atom J J Thompson

Describe the Plumb Pudding model of the atom A ball of positive charge with negative electrons embedded in it

Was the Plumb Pudding model correct? no

What experiment did Rutherford do? Alpha particle scattering

What did Rutherford's experiment reveal? Atoms have a central area of positive charge with electrons surrounding it

Who discovered that electrons are located in energy levels? Niels Bohr

What did Jame Chadwick discover about the atom? That the nucleus contains neutrons as well as protons

What did John Dalton contribute to our understanding of atomic theory? Matter is made up of descrete, spherical particles, known as atoms

Name the three subatomic particles proton, neutron, electron

Which particles are located in the atoms nucleus protons, neutrons

What is the charge of each subatomic particle? proton +1, neutron 0, electron -1

What is the mass of each subatomic particle? proton 1, neutron 1, elecrton ≈ 0

Name the three types of radiation alpha, beta and gamma

What is an alpha particle? two protons and two neutrons

What is a beta particle? an electron

What is gamma radiation? electromagnetic wave (NOT a particle)

What is the range of alpha radiation in air? short - 5 cm in air

What is the range of gamma radiation in air? unlimited in air

What's the range of beta radiation in air? medium - about 1 m

What will absorb (stop) alpha radiation? paper/skin

What will absorb (stop) beta radiation? about 5 mm aluminium

What will absorb (stop) gamma radiation? several centimetres of lead

What is the ionising power of alpha radiation? very high

What is the ionising power of beta radiation? medium

What is the ionising power of gamma radiation? low

What is meant by the ionising power of radiation? how likely it is to ionise atoms which it comes into contact with

How does alpha decay alter the mass number of the parent nucleus? decreases by 4

How does alpha decay alter the atomic number of the parent nucleus? decreases by 2

How does beta decay alter the mass number of the parent nucleus? stays the same

How does beta decay alter the atomic number of the parent nucleus? increases by 1

How does gamma radiation alter the mass and atomic number of the parent nucleus unchanged (energy is released as the particles in the nucleus reorganise to a lower energy arrangement)