Principles

Question 1

Mass number

Answer 1

Protons + neutrons

Question 2

Atomic number

Answer 2

Number of protons (as well as electrons)

Question 3

Relative atomic mass

Answer 3

Isotopes

Percentages of each mass no

Question 4

Relative formula mass

Answer 4

Mr of each part added

Question 5

Mole

Answer 5

6 x10 ^23 (Avogadro no)

Question 6

Calc for mol

Answer 6

Mass= Mr x mol

Question 7

Volume calc

Answer 7

Vol (dm3) = amount mol x 24

Vol (cm3) = amount mol x 24000

Question 8

Empirical formula

Answer 8

Simplest whole no ratio of atoms of each element in a compound

Question 9

Molecular formula

Answer 9

Exact number of atoms present on the formula of a compound

Need Mr and empirical formula
Find Ef mass and divide into Mr
Then times all parts by that no

Question 10

Conc equation

Answer 10

Mol= vol (cm3) x conc (mol/dm3)
——————————–
1000

Question 11

Diffusion

• 3 experiments

Answer 11

Bromine gas

Potassium 7 manganate

Hydrochloric acid and ammonia

Question 12

Percentage yield

Answer 12

Yield obtained
—————– X 100
Theoretical yield.

Yield= amount of product obtained

Question 13

Ionic compounds key words

Answer 13

Loss or gain of electrons
Metals + non metals
Ionic lattice
Electrostatic force of attraction between oppositely charged ions (ionic bond)

Giant ionic

Question 14

Covalent substances

Answer 14

Two non metals
Shared pair of electrons
Valence electrons

Question 15

Simple molecular

Answer 15

Diatomic elements
Low mp and bp
Forces of attraction are weak in comp to electrostatic forces
Often gases
When they change state the covalent bonds not usually broken (just the forces of attraction between the molecules)

Question 16

Methane

Answer 16

CH4

Question 17

Ammonia

Answer 17

NH3

Question 18

Ethane

Answer 18

C2H6

Question 19

Ethene

Answer 19

C2H4

Question 20

Giant covalent

Answer 20

Diamond, graphite, silicon dioxide

V high mp and bp

Question 21

Diamond

Answer 21

Each carbon with 4 other
Three dimensional structure formed
All 4 Valence electrons used
Covalent bonds are strong
V high mp and bp 
Very hard and abrasive
Doesn't conduct electricity
Cutting tools/ jewelry

Question 22

Graphite

Answer 22

Three bonds for each carbon
One free
A layered structure
Covalent bonds strong
Forces of attraction between layers weak
V high mp 
Soft and slippery
Conducts electricity
Lubricant
Electrodes for electrolysis

Question 23

Metallic crystals

Answer 23

Giant 3D lattice structure
Positive IONS arranged in a regular pattern in a sea of electrons
Valence electrons are detached from the atoms and are delocalised
Bond between positive ions and delocalised electrons is known as a metallic bond
High mp and bp
Good electricity conductors
Malleable and ductile

Question 24

Electrolysis def

Answer 24

Decomposition of a substance via the passing of an electrical current through it

Question 25

Molten electrolysis rules

Answer 25

Cathode - metal - negative electrode

Anode - nmetal - positive

Question 26

Molten sodium chloride

Answer 26

Cathode - sodium

Anode- chlorine

Question 27

Molten calc

Lead
Bromine

Answer 27

At cathode:

Pb2+ + 2e- > Pb

At anode:

2Br- > Br2 + 2e-

Question 28

Aqueous electrolysis

Answer 28

At neg = hydrogen or metal
At pos = oxygen or halogen

Hydrogen formed unless metal is below in reactivity series

Question 29

Equations of hydrogen in aqueous (electrolysis)

Answer 29

In neutral solutions of salts

2H2O + 2e- > H2 + 2OH-

In acidic conditions

2H+ + 2e- > H2

Question 30

Oxygen formed in aqueous (electrolysis)

Answer 30

2H2O > 2H2 + O2

4OH- > O2 + 2H2O + 4e-

Question 31

Electrolysis calc

Answer 31

Quantity (C) = current (A) x Time (s)

96500C = 1Faraday = 1mol electrons