Topic 5 - Formulae, Equations and Amounts of Substance

Question 1

Mole

Answer 1

Amount of a substance

Question 2

Avogadro’s constant

Answer 2

Number of atoms in one mole

6.02 x 10^23

Question 3

Molar mass

Answer 3

Mass of one mole expressed in

g/mol

Question 4

Empirical formula

Answer 4

Smallest whole number ratio of atoms of each element in a compound

Question 5

Molecular formula

Answer 5

Number of atoms of each element in a molecule

Question 6

Spectator ions

Answer 6

Ions that do not take part in the reaction

Question 7

Hydrate

Answer 7

A compound that has molecules of water of crystallisation

Question 8

Standard solution

Answer 8

A solution that has a known concentration

Question 9

Primary standard

Answer 9

A substance used in the preparation of a standard solution by weighing it

Question 10

Avogadro’s law

Answer 10

Equal volumes of gases contain the same number of molecules provided temperature and pressure are constant

Question 11

Molar volume

Answer 11

The volume of one mole of gas

Question 12

Displacement reaction

Answer 12

When a more reactive element takes the place of a less reactive element in a compound

Question 13

Precipitation reaction

Answer 13

One that produce an insoluble solid

Question 14

Error

Answer 14

A discrepancy between the value obtained in the experiment and the actual value

Question 15

Random error

Answer 15

Error when conditions are varied in an unpredictable manner

Question 16

Systematic error

Answer 16

Errors that are constant when you repeat an experiment

Question 17

Atom economy

Answer 17

Measure of the proportion of reaction atoms that become part of the desired product in the balanced equation