C2.1 Purity and Separating Mixtures

Question 1

Alloy

Answer 1

a mixture of a metal and at least one other element

Question 2

Balanced chemical equation

Answer 2

a model for a reaction showing formulae and number of units for all substances involved

Question 3

Boiling point

Answer 3

the temperature at which a substances changes from the liquid state to the gas state

Question 4

Carrier gas

Answer 4

an unreactive or inert gas used as the mobile phase in gas chromatography

Question 5

Chemical formula

Answer 5

a description of a compound or an element that uses symbols to represent the atoms present. Number show if more than one atom of an element is present

Question 6

Chromatogram

Answer 6

the pattern produced when separating a mixture using chromatography

Question 7

Chromatography

Answer 7

a separation method that relies on the distribution of a substance between a mobile phase and a stationary phase

Question 8

Condense

Answer 8

to change from the gas state to the liquid state

Question 9

Condenser

Answer 9

apparatus that can cool and condense a substance

Question 10

Crystallisation

Answer 10

the process by which crystals are formed during evaporation of a solvent from a solution

Question 11

Dissolve

Answer 11

the process in which a solute and solvent mix completely to form a solution

Question 12

Empirical formula

Answer 12

formula showing the simplest whole-number ratio of the atoms of each element in a compound

Question 13

Evaporate

Answer 13

when a substance turns from the liquid state to the gas state at a temperature below the boiling point

Question 14

Filtrate

Answer 14

liquid that passes through the filter during filtrations

Question 15

Filtration

Answer 15

the process by which insoluble substances are separated from soluble substances using a filter

Question 16

Fraction

Answer 16

in chemistry, substance separated during fractional distillation

Question 17

Fractional distillation

Answer 17

method for separating a mixture of liquids with different boiling points into different fractions

Question 18

Fractionating column

Answer 18

a piece of apparatus used to improve the separation of solvents during fractional distillation

Question 19

Gas chromatography

Answer 19

a type of chromatography that uses silica or alumina packed into a metal tube as the stationary phase, and an unreactive or inert carrier gas as the mobile phase

Question 20

Impure substance

Answer 20

material consisting of two or more different elements and/or compounds

Question 21

Insoluble

Answer 21

describes a substance that will not dissolve

Question 22

Melting point

Answer 22

the temperature at which a substance changes from the solid state to the liquid state

Question 23

Mixture

Answer 23

material consisting of two or more different substances, not chemically joined together

Question 24

Mobile phase

Answer 24

a substance in the liquid or gas state that moves during chromatography

Question 25

Paper chromatography

Answer 25

separation method that uses paper as the stationary phase and a solvent in the liquid state as a the mobile phase

Question 26

Periodic table

Answer 26

a table in which the elements are arranges in rows (periods) and columns (groups), in order of increasing atomic number

Question 27

Phase

Answer 27

in chemistry, a substance in the solid, liquid, or gas state

Question 28

Pure substance

Answer 28

consisting of just one element or compound

Question 29

Purity

Answer 29

a measure of how pure a substance is. A 100% pure substance consists entirely of one element or compound

Question 30

Relative atomic mass

Answer 30

The mean mass of an atom of an element compared to 1/12 the mass of a 12C atom, defined as 12 exactly. Its symbol is Ar

Question 31

Relative formula mass

Answer 31

Mr, the mean mass of an atom of an element compared to 1/12 the mass of a 12C atom, defined as 12 exactly. It is calculated by adding together the relative atomic masses for the atoms in the formula of a substance

Question 32

Relative molecular mass

Answer 32

relative formula mass applied to a molecular substance

Question 33

Residue

Answer 33

insoluble material left behind during filtration

Question 34

Rf value

Answer 34

Relative distance travelled by a substance during chromatography, calculated as: distance travelled by substance ÷ distance travelled by solvent

Question 35

Saturated solution

Answer 35

a solution containing the maximum mass of solute at a given temperature

Question 36

Simple distillation

Answer 36

method to separate a solvent from a solution

Question 37

Solubility

Answer 37

a measure of how much solute can dissolve in a given solvent at a certain temperature

Question 38

Soluble

Answer 38

a substance that will dissolve in a given solvent

Question 39

Solute

Answer 39

substance that dissolves in a solvent

Question 40

Solution

Answer 40

a mixture formed when one substance dissolves in another

Question 41

Solvent

Answer 41

a substance that can dissolve a solute to form a solution

Question 42

Stationary phase

Answer 42

a substance in the solid or liquid state that does not move during chromatography

Question 43

Thin-layer chromatography

Answer 43

a type of chromatography that uses silica or alumina spread on a plate as the stationary phase, and a solvent in the liquid state as the mobile phase

Question 44

Vapour

Answer 44

a substance in its gas state and below its boiling point