C4

Question 1

Relative atomic mass

Answer 1

The average mass of an atom of an element that takes into account the
abundance of the isotopes of the element

Question 2

Relative formula mass

Answer 2

The sum of the relative atomic masses of the atoms in a compound in the
numbers shown in the formula

Question 3

Carbon-12

Answer 3

The carbon isotope whose nucleus contains six protons and six neutrons. This
gives an atomic mass of 12

Question 4

Mole

Answer 4

An amount of a substance that has a mass in grams that is numerically equal
to its relative formula mass. The number of atoms, molecules or ions in this
amount of a substance is the Avogadro constant (6.02 × 1023).

Question 5

Avogadro constant

Answer 5

The number of atoms, molecules or ions in a mole of a given substance. It
has a value of 6.02 × 1023

Question 6

Concentrated

Answer 6

A solution with a large number of molecules of a substance in a given volume

Question 7

Concentration

Answer 7

The mass of solute per given volume of solution, measured in grams per dm3
(g/dm3
).
(HT only) The number of moles of solute per given volume of solution,
measured in moles per dm3 (mol/dm3)

Question 8

Molecular Formula

Answer 8

A formula that shows the actual numbers of atoms of each element in a
molecule

Question 9

Balanced equation

Answer 9

A representation of a chemical reaction using the formulae of the reactants
and products. It shows the number of atoms of each element involved in the
reaction

Question 10

Chemical formula

Answer 10

A series of chemical symbols showing the number of atoms of each element
in a compound

Question 11

Limiting reactants

Answer 11

The reactant in a chemical reaction that is completely used up and therefore
limits the amount of products

Question 12

Yield

Answer 12

The amount of a product obtained

Question 13

Percentage yield

Answer 13

The actual mass of product collected in a reaction dived by the maximum
mass that could have formed in theory, multiplied by 100

Question 14

Titration

Answer 14

Used to find the unknown concentration of a solution
Method: Slow addition of one solution of a known concentration to a known
volume of another solution of unknown concentration until the reaction
reaches neutralisation, which is often indicated by a colour change.

Question 15

End point

Answer 15

The point at which the a reaction between an acid and a alkali is complete
Use an acid/base indicator to show the end point of the reaction

Question 16

Concordant results

Answer 16

Results within 0.1cm3

of each other

Question 17

Pipette

Answer 17

A glass tube used to measure accurate volumes of liquids

Used to measure out or transfer small quantities of liquid

Question 18

Burette

Answer 18

A long glass tube with a tap at one end and markings to show volumes of
liquids: used to add precisely known volumes of liquids to a solution in a
conical flask