Definitions P2

Question 1

Matter

Answer 1

made up of particles whose properties determine the observable characteristics of matter and its reactivity.

Question 2

Mixture

Answer 2

a combination of two or more substances, where these substances are not bonded (or joined) to each other and no chemical reaction occurs between the substances.

Question 3

Heterogeneous

Answer 3

Consists of two or more substances, is a non-uniform composition and the different components can be seen.

Question 4

Homogeneous

Answer 4

One that is a uniform composition where the different components cannot be seen. All components are in the same phase.

Question 5

Pure Substances

Answer 5

cannot be separated into simpler components

Question 6

Elements

Answer 6

a substance that cannot be broken down into other substances through chemical means. On the periodic table. E.g.Hydrogen

Question 7

Compound

Answer 7

a substance made up of two or more different elements that are joined together in a fixed ratio. E.g. NaCl, FeS

Question 8

Brittle

Answer 8

Hard but likely to break easily

Question 9

Strength

Answer 9

the force it can resist before it deforms

Question 10

Malleable

Answer 10

ability to be hammered or pressed into a shape without breaking or cracking.

Question 11

Ductile

Answer 11

ability to be stretched into a wire

Question 12

Density

Answer 12

the mass per unit volume of a substance / how close together (dense) the particles in a material is packed (mass ÷ volume)

Question 13

magnetic properties

Answer 13

how easily it is attracted by magnets/magnetic objects

Question 14

Magnetism

Answer 14

a force that certain kinds of objects (magnetic objects) can exert on each other without physically touching. Surrounded by a magnetic field that gets weaker further from the objects.

Question 15

Thermal Conductivity

Answer 15

the extent to which a substance conducts heat

Question 16

Thermal Conductor

Answer 16

a material that allows heat to pass through easily

Question 17

Electrical Conductivity

Answer 17

the extent to which a material conducts electricity

Question 18

Electrical Conductor

Answer 18

a material that allows an electrical current flow of charge to pass through it. E.g. copper wire

Question 19

Electrical semi-conductor

Answer 19

a substance that can conduct electricity under some conditions, but not other, making a good medium for the control of electrical current.

Question 20

Electrical Insulator

Answer 20

a material that prevents the flow of charge/electrical current to pass through it. Non conductivity material that doesn’t carry charge. E.g. wood

Question 21

Diffusion

Answer 21

The movement of particles from an area of higher concentration to an area of lower concentration

Question 22

Brownian Motion

Answer 22

the random movement of microscopic particles suspended in a liquid or gas, caused by collisions between these particles and the particles of the liquid or gas.

Question 23

Melting/boiling point

Answer 23

how much heat has to be applied to change the material from a solid to a liquid or liquid to gas.

Question 24

Boiling Point

Answer 24

the temperature of which a liquid’s vapour pressure equals the external (atmospheric) pressure.

Question 25

Melting Point

Answer 25

the temperature at which a solid, given sufficient heat, becomes a liquid/change phase, called melting

Question 26

Freezing

Answer 26

the temperature at which a liquid changes its phase to become a solid, called freezing

Question 27

Evaporation

Answer 27

the change of a liquid to vapour at any temperature below the boiling point. It takes place at the surface of a liquid, where molecules have the highest kinetic energy that are able to escape.

Question 28

Condensation

Answer 28

the process during which a gas or vapour changes to a liquid/either by cooling or being subjected to increased pressure.

Question 29

Sublimation

Answer 29

the process during which a solid changes directly to a gas without passing through an immediate liquid phase.

Question 30

Melting

Answer 30

the process during which a solid changes to a liquid

Question 31

Freezing

Answer 31

the process during which a liquid changes to a solid

Question 32

Kinetic theory of matter (it's long)

Answer 32

it attempts to explain the behaviour of matter in different phases. It says that all matter is composed of particles which have a certain amount of energy which allows them to move at different speeds depending on the temperature (energy). There are spaces between particles and also attractive forces between particles when they come close together.

Question 33

Cation

Answer 33

a positive ion

Question 34

Anion

Answer 34

a negative ion

Question 35

Oxides

Answer 35

a compound with oxygen

Question 36

Atomic number

Answer 36

(Z) The number of protons in an atom of an element.

Question 37

Atomic mass

Answer 37

(A) The number of protons and neutrons in the nucleus of an atom.

Question 38

Isotope

Answer 38

The isotope of an element is made up of atoms which have the same number of protons as the atoms in the original element, but a different number of neutrons.

Question 39

Orbital

Answer 39

Defines the space in which an electron is most likely to be found.

Question 40

Electron configuration

Answer 40

The arrangement of electrons in an atom, molecule or other physical structure around the atomic nucleus.

Question 41

Valence electrons

Answer 41

The electrons in the outermost energy level.

Question 42

Core electrons

Answer 42

The electrons in an atom that are not valence electrons.

Question 43

A group

Answer 43

A column on the periodic table containing elements with similar properties.

Question 44

A period

Answer 44

A row on the periodic table.

Question 45

Atomic radius

Answer 45

A measure of the size of the atom.

Question 46

The first ionisation energy

Answer 46

The energy needed to remove 1 electron from an atom in the gas phase.

Question 47

Electronegativity

Answer 47

The tendency of atoms to attract electrons.

Question 48

Periodicity

Answer 48

It refers to the gradual change in physical and chemical properties of elements when moving from left to right.

Question 49

Dispersion

Answer 49

is a process whereby the particles of one substance are scattered all through another substance.

Question 50

A solution