Summary of each specification point for Edexcel C3.

1. C3Revision

2.  Qualitative Analysis is where you find out what
type of substance you have present.
 Quantitative Analysis is when you deduce the
amount of unknown sample you have.
 Water samples contain IONIC COMPOUNDS which
contain both CATIONS (positive) and ANIONS
(negative ions).
 Ion tests must only give a positive result or one
type of ion.

3.  Flame tests are
commonly used for
CATION (metals).
 Precipitate reactions
can also be used by
reaction the ionic
solution with SODIUM
HYDROXIDE as most
metal hydroxides are
insoluble in water.

4.  Testing for the Halogens
◦ This is performed by
acidifying the sample with
dilute Nitric Acid and then
reacting with Silver Nitrate
to form a precipitate.
◦ This reaction works by the Halogen displacing the
Nitrate in Silver Nitrate with the Halogen.
 Testing for Ammonium ions (NH4
+)
◦ Warm the solution to release the Ammonium ions
as a vapour
◦ It will turn damp red litmus paper blue.

5.  Imagine you have been given an unknown
sample…how can you test for the different
Ions.
 1)
 2)
 3)
 4)

6.  Ion identification is used in many different
industries. For example:
◦ Water Industry to test for dissolved ions (both
Halogens and other ions such as aluminium (linked
to Alzheimer's disease).
◦ Blood testing to test for different ions (Iron linked
to Anaemia, Sodium linked to kidney function).

7. Types of Water
 Soft water – contains low levels of ions (Na,
Mg) – easily produces a lather
 Hard water – contains lots of dissolved ions
(Ca, Mg) – produced scum not lather – used
lots of soap for cleaning
 Permanently hard water – cannot be easily
softened
 Temporarily hard water – can be softened by
boiling.

8. Calculating Concentration
 Concentrations of ions are calculated
generally in mgdm-3 or gdm-3.
 1dm3 is equal to 1000cm3 (1 litre)
 To calculate concentration use the following
formula:

9. Temporarily hard water
 This water is softened by boiling. It converts
the Calcium Hydrogen carbonate into
insoluble Calcium Carbonate (lime scale).
 Softening the water improves its ability to
form a lather and therefore reduce the
amount of soap required.

10. Softening Permanently
hard water
 This can be performed
using ION EXCHANGE.
This involves Sodium
ions (Na+) in the resin
displacing Calcium
(Ca2+) and Magnesium
(Mg2+) in the water
sample and softening
it.

12.  Substances can be measured in several ways.
They can be:
◦ Number of grams
◦ Number of particles
◦ Number of moles
 One mole of atoms is equal to the AVEGADRO
number of particles (6.02X1023)
 The mass of one mole of atoms is equal to
the Relative Atomic Mass number (top
number on periodic table).

13.  To calculate the number of moles use the
following formulas:

14. Making Copper
Sulphate from Copper
Oxide
1. React excess
oxide (insoluble)
with accurate
volume acid.
2. Filter excess
copper oxide and
collect copper
sulphate solution.
3. Evaporate solvent
(water) to
crystallise the salt.

15. Titrations
(preparing a salt from two soluble reactants)
 These reactions are NEUTRALISATION
REACTIONS.
 It involves accurately calculating the
volume of ACID required to neutralise
the BASE.
 An INDICATOR is used to deduce the
point of NEUTRALISATION (end point).
 A pipette is used to measure the base
accurately.
 A burette is used to add the acid
accurately.
 One the correct volumes have been
obtained then the reaction is performed
without the indicator

18. 1. Calculate number of moles of acid used.
2. Write balanced equation for reaction.
3. Using moles of acid information, deduce
number of moles of base required.
4. Calculate concentration of base.
This process also works the same in reverse.

19.  Electrolysis can only happen when IONIC
substances are either DISSOLVED or MOLTEN.
 Sodium metal is produced through the
electrolysis of MOLTEN Sodium Chloride.

20.  Oxidation is the loss of electrons and happens at the
ANODE.
 Reduction is the gain of electrons and happens at the
CATHODE.
 Sodium metal is used in street lights as it gives out a
yellow coloured light.
 Liquid Sodium is used as a coolant in Nuclear Reactors as
it has a high THERMAL CONDUCTIVITY.

22.  When you perform the electrolysis of a
molten salt you produce ions that are
discharged as atoms or molecules.
 For example, when you perform the
electrolysis of Lead Bromide Pb(II)Br2 you
obtain both Lead and Bromine gas.

23.  Electrolysis of salts in solution
◦ This involves both the electrolysis of the salt and
the electrolysis of water.
◦ The salt splits into its two component ions.
◦ The water splits into Hydrogen ions (H+) and
Hydroxide Ions (OH-).
◦ To perform electrolysis you must have INERT
(unreactive) electrodes as some of the products can
be highly corrosive.

26.  Purification of Copper
 An electrode of impure copper is used as the
ANODE.
 Pure copper is used as the CATHODE.
 The electrolyte is Copper Sulphate solution.

27.  Electroplating
 Electroplating is when a thin coat of valuable (or
unreactive) metal is applied to a cheaper (more
reactive) metal.
 Silver and Gold are metals that are commonly
used for electroplating.

28.  1 mole of = 24dm3 (at room temperature and
a gas atmospheric pressure)
A GAS SYRINGE is used to
collect gases during
reactions to allow molar
gas calculations to be
performed

30.  Nitrogenous fertilisers (ones that contain
Nitrogen) are manufactured from AMMONIA.
These fertilisers are used to promote plant
growth. These fertilisers increase the yield of
crops that are produced.
 If these fertilisers are used excessively then this
can lead to run off into rivers and lakes (or any
other water source). This results in excessive
plant growth (EUTROPHICATION). When these
plants die they decompose by bacteria which
uses up the OXYGEN.

31.  The HABER process is a REVERSIBLE reaction which will
reach DYNAMIC EQUILLIBRIUM.
 Dynamic equilibrium is where the FORWARDS and
BACKWARDS reactions are happening at the same rate.

32.  When AMMONIA is formed it releases heat
(EXOTHERMIC). This is the FORWARDS reaction.
 The reverse reaction will be the opposite which
makes it ENDOTHERMIC (takes in heat)
 When DYNAMIC EQUILLIBRIUM is reached these
two reactions occur at the SAME RATE.
 Adjusting the temperature and pressure will
affect the position of the equilibrium, favour the
PRODUCT or REACTANT.

33. N2 + 3 H2 ⇌ 2 NH3
 Reactant = 4 molecules
 Products = 2 molecules
Pressure and the Haber process
 If you increased the pressure of the reaction the equilibrium
would favour the PRODUCTS (move to the right). This is because
the particles are being forced closer together and therefore more
likely to react.
Temperature and the Haber process
 As the reaction is EXOTHERMIC it favours cooler conditions (it
releases energy into the surrounding environment).
 An increase in temperature would move the equilibrium to the
left (favour the reactants).
 A low temperature would increase the yield but slow the rate of
reaction.

34.  Optimal conditions are used to ensure that the maximum
possible yield is produced safely and at a sufficient rate to
be economically viable.
 Temperature – approx. 450OC
 Pressure – 200atm (200 times atmospheric)
 Catalyst – Iron catalyst
 A catalyst increases the rate of reaction without ever being
used in the reaction. It works by lowering the activation
energy for the reaction (energy required for a successful
collision)
 If the temperature or pressure is too high then there can
be safety implications and too low will result in a lower
yield.

35.  Ethanol (alcohol) can be produced by the
fermentation of CARBOHYDRATES (sugars).
 Fermentation occurs when YEAST convert sugars
into alcohol. The yeast act as an ENZYME.
 For this to happen successfully the following
conditions must be sustained:
◦ Kept warm (allow the bacteria to work successfully, too
hot will kill them)
◦ Anaerobic conditions (no oxygen)

36.  Different types of alcoholic drink contain different
percentages of ethanol. The higher the alcohol content
the higher % it is given.
 1 unit of alcohol = 10cm3 pure ethanol
 The effects of alcohol are:
◦ Slower reaction times
◦ Violent/aggressive behaviour
◦ Loss of balance/coordination
◦ Vomiting and fainting
◦ Dehydration
 Prolonged alcohol consumption can result in an increased
risk of HEART DISEASE, STROKE or LIVER CIRROHISIS.
 Alcoholic spirits are made by FRACTINAL DISTILLATION
where the ethanol is removed first and the water is left
behind (increasing the alcoholic content)

37. Ethanol can be produced in two main ways:
1. Fermentation – sugars are turned into ethanol and
carbon dioxide through the anaerobic respiration of
YEAST.
2. Hydration of Ethene (crude oil fraction) – reacting
ethene with steam in the presence of a catalyst
(addition reaction)

38.  Each method of Ethanol production has both
social, environmental and economical advantages
and disadvantages.
 This information needs to be evaluated to
determine the best method of production for
individual cases.
Making Ethene
 Ethene can be made by the cracking of CRUDE
OIL but also the DEHYDRATION of Ethanol.

39.  Alkanes – a
hydrocarbon
containing only
C-C bonds.
 Alkenes – a
hydrocarbon
containing at least
one C=C bond.
 Alcohol – a
hydrocarbon
containing at least
one –O-H group.
A HOMOLOGOUS series is a series of compounds that have the same
general formula and similar chemical properties but have variation in
boiling points.

41.  Ethanoic acid is a CARBOXYLIC ACID.
 It is the active ingredient in VINEGAR.
 It is produced by the OXIDATION of ethanol (under aerobic
conditions).
 It has a sharp, sour taste and can be used as a PRESERVATIVE.
 Ethanoic acid reacts with metals to form salts (ending –
ethanoate).
 Carboxylic acids react in the same way as normal acids. They are
classified as weak acids.
 Carboxylic acids are named in the same way as other
homologous series. Their ending is –anoic acid.
 Their functional group is –COOH.

42.  Esters are made during the reaction of ALCOHOLS and
CARBOXYLIC ACIDS.
 They are commonly used as FLAVOURINGS and FRAGRANCES as
they have distinctive smells and tastes.
 Ethanol reacts with ethanoic acid to from the ester ETHYL
ETHANOATE.
 Esters can also be turned into FIBRES to make FABRICS –
POLYESTER.
 Polyesters can be recycled to form FLEECE.

43.  Fats and Oils are big esters. The only difference is fats are SOLID
at room temperature where as oils are LIQUID.
 Soaps can be made from fats and oils by heating with a
concentrated alkali.
 Oils are commonly UNSATURATED (contain C=C bonds).
 Fats are SATURATED (contain C-C bonds).
 To turn an oil into a fat you must HYDROGENATE it (addition of
Hydrogen)

44.  How do Soaps work?
 A soap can be shown as a
tadpole shape – head is water
loving (HYROPHILLIC) and tail is
water hating (HYDROPHOBIC).
 The head has a negatively
charged oxygen ion (anion).
 The tail is a hydrocarbon (water
hating)
 Hydrophobic tail sticks into
grease.
 Hydrophilic end sticks out to
attract water.
 Grease particle surrounded by
hydrophilic heads.
 Removed by water attraction
(grease can now mix with water)