Deirdre Brennan
MPC
Leaving certificate Chemistry Pass level Revision notes
Q.1
Making ethene
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Making ethyne
Glass wool soaked in ethanol
Aluminium oxide /white solid
Suck back
Turns bromine water colourless-test for
unsaturation
Turns KMn04 purple to colourless- test for
unsaturation
Called a dehydration reaction
Food ripening
Burns with luminous flame
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Water
Calcium carbide/grey solid
Acidified copper sulphate to remove
impurities
Turns bromine water colourlessunsaturation test
Burns with luminous sooty flame
Oxy acetylene Welding
Sooty flame caused by lack of 02
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Deirdre Brennan
Making ethanal
MPC
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sodium dichromate(orange 6+)
ethanol
anti bumping granules
conc sulfuric acid added slowly in ice as reaction
is exo
colour change to (green 3+)
distilled immediately to stop ethanal turning to
ethanoic acid
ice water-stop ethanal evaporating,
boiling point = 210C
water in at bottom, out at top
excess ethanol to stop ethanal turning to
ethanoic acid
impurities = water, ethanol, ethanoic acid,
redox reaction
Test for presence of ethanal is fehlings (I) + (II).
Blue to red (Identifies C=0)
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Deirdre Brennan
MPC
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Making ethanoic acid
2008
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Making soap
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sodium dichromate in excess(orange
6+)
ethanol
anti bumping granules
conc acid added slowly as reaction is
exothermic
colour change to (green 3+)
refluxed first and then distilled
water in at bottom, out at top
excess sodium dichromate to allow
ethanol to fully oxidize to ethanoic acid.
impurities = water, ethanol, ethanal
redox reaction
use Bunsen burner instead of hot plate
as ethanoic acid bp = 1180C
Precautions:add ethanol mixture drop
by drop into flask+keep flask cooled
under running water
Fat
Sodium hydroxide
Ethanol which is solvent
Anti-bumping granules
reflux
then distil to remove ethanol
filtered through brine to precipitate out soap
wash with cold water to remove NaOH
The ionic part of the soap molecule is water-soluble
while the non-polar hydrocarbon part is soluble in
oil and grease.
Reflux apparatus used to ensure that the hydrolysis
of the fat is as complete as possible. If the mixture
If not refluxed ethanol would be lost.
Base hydrolysis
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Deirdre Brennan
Extracting clove oil
MPC
Clove oil contains component molecules whose
boiling points are quite high. Heating them to their
boiling point would be destructive.
The component molecules found in clove oil are
often relatively non-polar and will therefore be
more soluble in the non-polar solvent than in
water.
One of the major components of clove oil is
eugenol, an aromatic compound that can burn skin.
Gloves should be worn when handling the product
of the experiment.
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Deirdre Brennan
MPC
Q.2 Titrations
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HCl and Na2C03 titration
label pipette, burette, wash bottle, volumetric flask
standard solution-one whose concentration is known exactly
volume of Sodium carbonate solution measured using pipette
volume of HCl solution measured using burette
How do you make a standard solution of sodium carbonate?
o Weigh out quantity of Standard solution in a clock glass
o Dissolve in deionised water
o Transfer this volume + any remaining Standard solution using wash
bottle into a 250ml volumetric flask
o Bring to the calibrated mark with deionised water.
o Stopper , invert and shake 20 times
indicator = methyl orange
ratio 2: 1 acid: base
V A MA = V B M B
NA
nB
Q.2
hydrochloric
acid
sodium
hydroxide
titration
2007
2005
2002
1. label pipette, burette, wash bottle, volumetric flask
2. standard solution-one whose concentration is known
exactly
3. volume of Sodium hydroxide solution measured using
pipette
4. Describe correct procedure for rinsing and filling a
pipette
 Rinse with deionised water
 Using a filler fill to the calibrated mark with base
 Empty the base from the pipette by tipping the last
drop at the side of glass
5. Describe correct procedure for rinsing and filling a
burette
 rinse with deionised water
 using a funnel fill burette to 0 with acid.
 Make sure you read level of meniscus
 Open tap to allow acid to fill bottom of burette
6. volume of HCl solution measured using burette
7. describe how you would make a salt
8. indicator = methyl orange
9. end point = permanent pink
10. ratio 1: 1 acid: base
11. calculation
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Deirdre Brennan
MPC
Example:
25ml of 0.1M NaOH neutralized 20ml of xM concentration
of HCL. Find x?
V acid =20
M acid =x
n acid =1
V base=25
M base=0.1
n base =1
VA MA
=
V
Na
20 x
1
B
MB
nB
X
=
25 x 0.1
1
concentration of HCl = 0.125m/l
conc of HCL in g/l = 36.5 x .125 = 4.6 g/l
Mr of HCl = 1 + 35.5 = 36.5g
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Deirdre Brennan
MPC
Rates of Reaction experiments can come up in various questions
Making oxygen from hydrogen peroxide and manganese dioxide
1. Draw the diagram on page 211
2.
catalyst is a chemical that speeds up or slows down the rate of a chemical reaction
but does not change itself.
3. Rate of reaction is the change in concentration of a reactant per unit time.
1. Catalysis
Three types
Heterogenous = reaction involving gas/liquid, gas/solid, solid/liquid
Homogenous = gas/gas, solid/solid, liquid/liquid
Autocatalysis= where product of experiment becomes a cataylst
2. Three types of metals that are used in catalytic converters
Palladium, rhodium, platinum
3. Lead damages a catalytic converter
Metal
Potassium
Lithium
Barium
Strontium
Copper
Q.5 Revision of flame tests
Colour
purple
Crimson
Green
Red
Green
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Deirdre Brennan
Sodium
Chloride
Sulphate
Carbonate
Nitrate
MPC
Yellow
Revision of anion tests
Add silver nitrate
Add barium chloride
Add HCl
Add iron sulphate and
sulphuric acid
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White ppt
White ppt
Fizzing occurs
brown ring
Deirdre Brennan
MPC
Q.4
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Calculating ppm (parts per million)
Calculating % of element in compound
Bomb calorimeter
OIL RIG
Equilibrium constants
calculate the pH of an acid/base
Anion tests
Endothermic/exothermic reactions
Atomic radii increase going down group.
Atomic radii decrease going across a period.
Uses of organic compounds
o Methanoic acid= ant stings
o Propanone= nail varnish remover
o Ethanoic acid = vinegar
o Benzoic acid= food preservative
o Methyl benzene = safe solvent
o Ethene gas= food ripening
o Ethyne gas= welding
o Ethanol = beer/wine
o Methane = home heating
Temporary hard water = Calcium carbonate permanent hard water = calcium
sulphate
Calculations on ppm ( mg/l)
A 100cm3 sample of seawater contains
0.022g of SS. Calculate the conc. Of SS in ppm
Step 1. Change grams to milligrams
0.022g X 1000 = 22mg in 100cm3
Step 2. Find 1cm3 22÷ 100 = 0.22mg/ml
0.22 X 1000 = 220mg/litre
Step 1 : Find relative molecular mass of
MgSO4
24 +32 + 16(4) = 120g
Step 2 : 24/120 x % = 20%
Calculate % of magnesium in
( MgSO4)
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Deirdre Brennan
MPC
Question 5
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Scientist
John Dalton
Rutherford
J.J Thompson
Chadwick
Bohr
Crookes
Millikan
Newlands
Dobereiner
Mendeleev
Moseley
Humphrey Davy
Becquerel
Marie Curie
Boyle(plunger)
16. J
Charles(hot
balloon)
17. Avogadro
18. Arrhenius
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Discovered
Atomic theory
Nucleus, proton
electron
Neutron
Electrons orbit nucleus in fixed paths
Cathode ray tube
Charge/mass of electron
Octaves
Triads
Gaps/atomic mass
Atomic number
Discovered many elements such as Na/Mg/K
Radioactivity
Radium/polonium
1.At constant temp a 2.fixed mass of gas , the 3.vol is 4.
inversely proportional to 5.pressure p = 1/v
air 1.At constant pressure a 2.fixed mass of gas , the 3.vol is 4.
directly proportional to 5.temperature on Kelvin scale (
T ∞ V)
1 mole = 6 x 10 23 atoms
Definition of an acid/base
Atomic number = no. of protons in nucleus of an atom
Mass number = no. of protons and neutrons in nucleus of an atom
Electronegativity= it’s the force of attraction that an atom has for the shared
pair of electrons in a covalent bond.
Relative atomic mass= is the mass of an atom compared to 1/12 the mass of
the carbon-12 isotopes.
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Deirdre Brennan
Shapes of molecules
Molecule
Methane ( CH4)
MPC
Drawing
Water (H20)
Ammonia(NH3 )
Boron trichloride (BCl3)
Ethyne ( C2H2)
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Covalent bonding= electrons are shared
Ionic bonding= electrons are taken/given
Valency = group number of that element
Radioactivity
1.
Alpha Particle(helium nuclei) 2 neutrons+ 2 protons .
2.
Beta Particle-high energy electron- it’s a neutron that turns into a proton and a high
energy electron is emitted
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Deirdre Brennan
MPC
3.
Gamma readiation-high electromagnetic radiation when nucleus changes shape.
Uses
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•Smoke Detectors contain a weak source made of Americium-241.
Carbon-14 Dating
Cancer treatment
Sterilising
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Deirdre Brennan
MPC
Q.6
Hydrocarbons are compounds that contain hydrogen and carbon only.
1. Fuels are organic compounds and when they are combusted they
release large quantities of energy.
2. LPG is liquid petroleum gas.
3. Octane number is ability of a fuel to reduce knocking
4. Aromatic compound has a benzene ring
5. hydrogen is a fuel for space rockets but is very explosive
6. Lead used to be used for increasing octane number but causes
health problems.
7. Isomerisation, catalytic cracking , dehydrocyclisation and adding
oxygenates(ethanol has octane no of 111, excellent fuel) are ways to
increase octane number
8. Adding oxygenates lower pollution
9. MTBE( methyl tertiary butyl ether)
10. 2,2,4 trimethyl pentane octane no is 100
Fraction
Refinery gas
petrol
Naphtha
Kerosene
diesel
Lubricating oil
Fuel Oil
Bitumen
Use
Domestic gasb
Motor fuel
Petrochemical
industry(Plastics)
Aviation fuel
Motor fuel
Reduce wear of
engines
ships
Tar
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Deirdre Brennan
MPC
Revising Question 8
Formula
Name
C2H50H
Ethanol
C2H2
Ethyne
CH3CHO
Ethanal
CH3COOH
Ethanoic acid
CH3 CH2 0Na
Sodium ethanoate
CH3 CH2 Cl
1, chloro ethane
Shape
tetrahedral
planar
planar
tetrahedral
tetrahedral
tetrahedral
CH2BrCH2Br
CH3 CH3
C2H4
tetrahedral
tetrahedral
Planar
Formula
C2H50H
C2H2
CH3CHO
CH3COOH
CH3 CH2 Cl
CH2BrCH2Br
CH3 CH3
C2H4
1,2 dibromoethane
ethane
ethene
Mechanism
Ethane going to ethanol is called an
addition reaction
Ethanol going to ethane is called an
elimination reaction
CH2 CH2 (ethene) going to
CH3 CH2 Cl is called an addition
reaction
C2H50H going to CH3COOH is called
oxidation reaction.
Bond type
Saturated
Unsaturated
Unsaturated
Unsaturated
saturated
Saturated
saturated
unsaturated
Questions on water(generally question 9)
Treatment of water for drinking
Stages
What happens
Screening
Large insoluble solids removed
Flocculation
Aluminium sulfate added to water to help suspended solids to clump
together
Sedimentation
Suspended solids allowed to settle to bottom of tank.
Filtration
Water passed through beds of sand and gravel to remove suspended
solids
Fluorination
Put in to prevent tooth decay
Chlorination
Kills bacteria
pH adjustment
Lime or acid added
Stages
Primary
Secondary
tertiary
Treatment of sewage
What happens
Sewage passed through grids to remove dense solids.
Sewage then put into sedimentation tanks where suspended solids allowed
sink to bottom.
Sewage allowed to be broken down by bacteria
Removal of phosphates and nitrates
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Deirdre Brennan
MPC
Sewage causes eutrophication which causes fish kills and polluted river water.
Phosphates and nitrates cause over enrichment of water causing eutrophication.
Silage effluent and human effluent from septic tanks can cause eutrophication.
Temporary hardness in water removed by boiling.
Hardness in water caused by Mg2+ and Ca 2+ ions.
Temporary hardness caused by limestone.
Permanent hardness caused by Calcium sulphates (CaS04) from rock such as gysum.
 What is the % of Ca in CaC03?
 A 100cm3 sample of sea water contains 0.022grams of suspended solids. Calculate
the conc. Of suspended solids in ppm.
 Biochemical Oxygen Demand. The five day Biochemical Oxygen Demand of
a water sample is the amount of dissolved oxygen taken up by bacteria in
measured after 5 days incubation in the dark at 20 0C.
Acids & bases
•Arrhenius acid is a substance that breaks down in water to produce H+ ions.
•Arrhenius base is a substance that breaks down in water to produce OH- ions.
•Strong Base is Sodium Hydroxide (used for cleaning drains)(NaOH)
•Weak base is ammonia.(NH3)
•Strong acid is HCl, H2SO4, HNO3
•Weak Acid is vinegar(ethanoic acid)
•pH is the measure of acidity or basicity
•pH measured using universal indicator
•BL acid is proton donor
•BL base is proton acceptor
•Neutralisation is reaction between an acid and a base that makes salt and water.
•Everyday example is rubbing wasp sting with vinegar to neutralise the base
•Putting lime on soil to neutralise acidic soil.
 limitation of pH scale not accurate for concentrated solutions
Calculate the pH of a 0.01M solution of NaOH
pH = -log10[0.01]= 14-2 = 12
Concentration of a solution of 4.0g/l of sodium hydroxide is Calculate the pH?
•Step 1 : 4/40 = 0.1M
•Step 2
pH = -log10[0.1]= 14-1 = 13
Calculate the pH of a 0.01M solution of H2S04
pH = -log10[0.01 x2]= 1.7
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Deirdre Brennan
MPC
Le Chatelier’s principle states that when a stress is applied to a system the system moves to
relieve the stress.
What does the symbol
tell us?
Chemical equilibrium is a state of dynamic balance where the rate of the forward reaction
equals the rate of the reverse reaction.
Rates of Reactions
 The rate of a reaction is the change in concentration per unit time of any one
reactant or product.
 The rate of reaction at a particular instant in time is called the instantaneous rate.
Factors affecting reaction rate
(i)
Nature of reactants
Ionic reactions are fast because they merely involve the coming together of
oppositely charged ions.
Covalent reactions are usually slower at room temperature, because they
involve breaking covalent bonds.
(ii)
Particle size
(iii)
Concentration
The rate of a chemical reaction increases with increased concentration. When
sodium thiosulphate is reacted with HCl , a precipitate of sulphur is formed.
This sulphur is in the form a cloudy yellow suspension. By increasing the
concentration of the sodium thiosulphate solution the rate at which the sulphur
appears increases also.
(iv)
Pressure
Increased pressure increases reaction rate.
(v)
Temperature
All reactions are faster at higher temperatures.. When sodium thiosulphate is
reacted with HCl , a precipitate of sulphur is formed. This sulphur is in the form
a cloudy yellow suspension. By increasing the temperature of the reaction
solution the rate at which the sulphur appears increases also.
(vi)
Catalysts
catalyst is substance that alters the rate of a chemical reaction but is not
consumed in the reaction.
(a)
General properties of catalysts
1. Catalysts are recovered from a reaction unchanged with the same
chemical properties.
2. Catalysts are specific. Enzymes are biological catalysts that have very
specific functions.
3. Catalysts needed in small amounts to function.
4. Equilibrium is reached quicker by using a catalyst.
5. Catalysts can be destroyed by catalytic poisons. Arsenic inhibits the
action of certain enzymes in the body.
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Deirdre Brennan
MPC
(b) Catalytic Converters
Platinum, Palladium and Rhodium
Toxic fumes from cars : CO and NO are adsorbed onto the surface of these
metals
C0 to CO2
NO to NO2 .
Collision Theory and Activation Energy
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A chemical reaction between two substances is the result of their
molecules colliding together. These colliding molecules must
possess a minimum amount of energy for a reaction to occur. When
an effective collision occurs bonds are broken and new bonds are
formed.
The Activation Energy is the minimum energy which colliding particles
must have for a reaction to occur.
Chromatography
is a separation technique in which a mobile phase carrying a mixture moves in
contact with a stationary phase.
Stationary phase
= filter paper
Mobile phase= solution e.g methanol + food colouring/felt-tippedmarkers/mixture
of indicators
TLC used for separating out impurities in drugs
Mass spectrometry
 Used to find relative molecular mass of compound
HPLC
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High performance liquid chromatography
Used to detect growth promoters in food/concentration of caffeine in drinks
Gas Chromatography
 Used in detecting alcohol/drugs in urine samples
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Deirdre Brennan
MPC
Q.10+ 11 Gas Laws
Boyle’s law states that at constant temperature the volume of a fixed mass of gas is
proportional to its pressure.
Charle’s law :At constant pressure, the volume of a fixed mass of gas is directly proportional
to its temperature measured in the Kelvin scale.
Avogadro’s Law states that equal volumes of gases contain equal numbers of molecules
under the same conditions of temperature and pressure.
Combined gas law solves the problem of the relative molecular mass of a volatile gas
How confident am I that I have learnt and know my notes on the experiments
Mandatory Experiments
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8)
Flame tests
Preparation and properties of Ethene
Preparation and properties of Ethyne
Determine the heat of Neutralisation of HCl and NaOH
Preparation and properties of Ethanal
Preparation and properties of Ethanoic Acid
Preparation of Soap
Chromatography
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10)
11)
12)
Determination of total suspended and dissolved solids in water sample + pH
To standardise a HCl solution using a standard solution of Na2C03
To prepare a sample of sodium chloride by neutralizing with NaOH with HCl.
Benzoic acid
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14)
Extracting clove oil
Anion tests
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Equilbrium reactions(looking at Le Chatelier’s principle.
Looking at rate of production of oxygen
To show how concentration and temp. affect the rate of a reaction.
Find relative molecular mass of volatile gas
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