Leaving Cert Chemistry

Leaving Cert Chemistry helpful information:

General Information

Subject Overview

The subject aims to provide a relevant course for students who will complete their study of chemistry at this level while, at the same time, providing a foundation course for those who will continue to study chemistry or related subjects following completion of their Leaving Certificate. The syllabus consists of approximately 70% pure chemistry; the remaining 30% deals with the social and applied aspects of chemistry.

Content

Subject content is presented at Ordinary level and Higher level under the headings:

  1. Periodic Table and Atomic Structure
  2. Chemical Bonding
  3. Stoichiometry, Formulas and Equations
  4. Volumetric Analysis
  5. Fuels and Heats of Reaction
  6. Rates of Reaction
  7. Organic Chemistry
  8. Chemical Equilibrium
  9. Environmental Chemistry: Water
    Option 1
    1A: Additional Industrial Chemistry
    1B: Atmospheric Chemistry
    Option 2
    2A: Materials
    2B: Additional Electrochemistry and the Extraction of Metals

Mandatory experiments are listed at the end of each main syllabus section.

Assessment

Leaving Certificate Chemistry is assessed by means of a terminal examination paper at each level. Students are required to keep a record of their practical work over the two years of the course.

Subject/Course Choice

If students are looking to do a course in Science ,Information Technology ,Engineering or Medicine at third level this is a very good subject to study for the Leaving Certificate. If students excelled at Science and Maths at Junior Certificate this is very likely a good match for them if they want to pursue the above courses.

Download Past State Exam Papers
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Definitions

Chemistry Definitions and when they last appeared on the paper

  • An energy level is the fixed energy value that an electron in an atom may have.

2008, 2007

  • Heisenberg uncertainty principle: is is impossible to measure at the same time both the velocity and the position of an electron.

2009

2006

  • An orbital is a region in space within which there is a high probability of finding an electron.

2011, 2010, 2006, 2005

  • An element is a substance that cannot be split up into simpler substances by chemical means.

 

  • An element is a substance all of whose atoms have the same atomic number

 

  • The periodic law: when elements are arranged in order of increasing atomic number the properties of the elements vary periodically.

 

  • The atomic number of an atom is the number of protons in the nucleus of that atom.

2011

  • The mass number of an element is the sum of the number of protons and neutrons in the nucleus of an atom of that element.

 

  • Isotopes are of the same elements that have different mass numbers due to the different number of neutrons in the nucleus.

2011

2009,

2006,

2005

  • A radio isotope is a radioactive isotope or the radioactive form of the element.

 

  • Relative atomic mass is the average of the mass numbers of the isotopes of the element as they occur naturally, taking their abundancies into account and compared with 1/12thof the mass of the carbon – 12 isotopes.

2011

2006

2004

  • The aufbau principle: when building up the electronic configuration of an atom in its ground state, the electrons occupy the lowest available energy level.

 

  • Pauli exclusion principle: no more than two electrons can occupy an orbital and they must have an opposite spin.

 

  • Hund’s rule: when two or more orbitals of equal energy are available electrons occupy them singly before filling them in pairs.

 

  • A compound is a substance that is made up of two or more different elements combined together chemically.

 

  • The octet rule states that when bonding occurs, atoms tend to reach an electron arrangement with eight electrons in the outermost shell.

 

  • An ionic bond is the force of attraction between oppositely charged ions in a compound.

 

  • A transition element is one that forms at least one ion with a partially filled d sub-level.

 

  • A covalent bond is formed when two atoms share a pair of electrons.

2005

  • The valency of an element is the number of atoms of hydrogen or any other monovalent element with which each atom of that element combines.

 

  • Electro negativity is the relative attraction that an atom in a molecule has for the shared pair of electrons in a covalent bond.

2010

2008

2006

2005

  • Law of conservation of mass: The total mass of the products of a chemical reaction is the same as the total mass of the reactants.

 

  • Law of conservation of matter:  In any chemical reaction, matter is neither created nor destroyed, but merely changes from one form to another.

 

  • The atomic radius of an atom is defined as half the distance between the nuclei of two atoms of the same element that are joined together by a single covalent bond.

2007

2005

 

  • The first ionisation energy of an element is the energy required to remove the most loosely bound electron from a neutral gaseous atom.

2009

2004

  • Radioactivity is the spontaneous breaking up of unstable nuclei with the emission of one or more types of radiation.

2011

2010

2004

  • The half life of an element is the time taken for half of the nuclei in any given sample to decay.

2010

 
  • The relative molecular of a substance is the mass of one molecule of that substance compared with one twelfth of the mass of the carbon – 12 – isotope.

 

  • One mole of a substance is the amount of that substance which contains 6 x 10 23particles of that substance.

2011

2005

  • Number of moles = mass in grams / mass of one mole.

 

  • Boyle’s law states that at constant temperature the volume of a fixed mass of gas is inversely proportional to its pressure.

 

  • Charles’ Law states that at constant pressure the volume of a fixed mass of gas is directly proportional to its temperature measure on the kelvin scale.

2004

  • Gay lussacs law – states that in a reaction between gases, the volumes of the reacting gases and the volumes of any gaseous products are in the ratio of small whole numbers provided that the volumes are measured at the same temperature and pressure.

2010

 
  • Avogadro’s law states that equal volumes of gases contain equal numbers of molecules under the same conditions of temperature and pressure.

2011

2009

2007

2005

2004

  • An ideal gas is one that obeys all of the assumptions of the kinetic theory of gases under all conditions of temperature and pressure.

2010

2006

2004

  • The empirical formula of a compound is the formula which gives the simplest whole number ratio of the elements in the compound.

 

  • The molecular formula of a compound is the formula that gives the actual number of each atom in the molecule.

 

  • Arrhenius definition for an acid is:  an acid is a substance that dissociates in water to produce H+ ions

 

  • Arrhenius definition for a base is: a base is a substance that dissociates in water to produce OH- ions.

 

  • Bronsted Lowry definition: an acid is a proton donor.

2010

2007

2005

 

  • Bronsted Lowry definition: a base is a proton acceptor.

2005

  • A conjugate acid – base pair is any pair consisting of an acid and a base which differ by one proton.

 

  • Neutralisation is the reaction between an acid and a base to form a salt  and water.

2010

2009

2007

2006

  • A salt is the substance formed when the hydrogen atom in an acid is replaced by a metal or ammonium ion.

 

  • The concentration of a solution is the amount of solute that is dissolve in a given volume of a solution.

 

  • Parts per million = number of milligrams per litre.

 

  • The molarity of a solution is the number of moles of solute per litre of solution.

 

  • Number of moles = volume x molarity / 1000

 

  • A standard solution is a solution of precisely known concentration.

 

  • A primary standard is a substance which can be obtained in a stable, pure and soluble solid form so that it can be weighed out and dissolved in water to give a solution of accurately known concentration.

2007

  • Oxidation of an element takes place when it loses electrons.

2008

  • Reduction of an element takes place when it gains electrons.

 

  • Oxidation number is the charge that an atom has or appears to have when electrons are distributed according to certain rules.

2008

2006

2005

  • Oxidation is the increase in oxidation number

2008

2006

2005

  • Reduction is a decrease in oxidation number.

 

  • The rate of reaction is the change in the concentration per unit time of any one reactant or product.

2011

2007

2004

  • The instantaneous rate of reaction is the change in concentration per unit time of any one reactant or product at a given moment of time.

 

  • A catalyst is a substance that alters the rate of a chemical reaction but is not consumed in the reaction.

 

  • The activation energy is the minimum energy which colliding particles must have for a reaction to occur.

2011

2010

2009

2006

  • Chemical equilibrium is a state of a dynamic balance where the rate of the forward reaction equals the rate of the backward reaction.

2010

2008

2004

  • Le Chateliers principle is where a system is in equilibrium is subjected to a stress i.e. a change in temperature, pressure, or concentration, then the system will alter so as to oppose the effect of the stress.

2010

2008

2007

2006

2005

  • If a stress is applied to a system at a equilibrium the system readjusts to relieve the stress applied

 

  • pH may be defined as pH = -log10[H+]

2011

2004

  • pOH may be defined as pOH = -log10[OH-]

 

  • The ionic product of water (Kw) = [H+][OH-]

2008

  • pH + pOH = 14

 

  • Hard water is water that will not easily form a lather with a soap

2006

  • Biochemical oxygen demand is the amount of dissolved oxygen consumed by biological action when a sample of water is kept at 20 degrees celcius in the dark for five days.

2011

2005

  • Eutrophication is the enrichment of water with nutrients.

2007

  • Electrolysis is the use of electricity to bring about a chemical reaction.

 

  • Electroplating is a process where electrolysis is used to put a layer of one metal on the surface of another.

 

  • The electrochemical series is a list of elements in order of their standard electrode potentials.

 

  • Organic chemistry is defined as the study of the compounds of carbon.

 

  • Hydrocarbons are compounds containing carbon and hydrogen only.

2009

  • A homologous series is a group of compounds all members of which contain the same function group of atoms and successive members of a homologous series differ in size by CH2

2011

2006

  • A functional group is a group of atoms on which the characteristic properties of a particular homologous series depend.

 

  • Heat of reaction is the heat change when the number of moles of a reaction indicated in the balanced equation for the reaction react completely.

 

  • The heat of combustion of a substance is the heat change when one mole of a substance is completely burned in excess oxygen.

2010

  • Bond energy is the energy required to break one mole of covalent bonds to separate the neutral atoms.

2009

  • The heat of formation of a compound is the heat change that takes place when one mole of a compound in its standard state is formed from its elements in their standard states.

2004

  • Hess’s law states that if a chemical reaction takes place in a number of stages the sum of the heat changes in the separate stages in equal to the heat change if the reaction is carried out in one stage.

 

  • A functional group is an atom or group of atoms which is responsible for the characteristics properties of a series of organic compounds.

 

  • A substitution reaction is a chemical reaction in which an atom or group of atoms in a molecule is replaced by another atom or group of atoms.

 

  • The mechanism of a reaction is the detailed step – by – step description of how the overall reaction occurs.

 

  • An addition reaction is one in which two substances react together to form a single substance.

 

  • Catalytic cracking is the breaking down of long chain hydrocarbon molecules into smaller molecules.

2007

  • The octane number of a fuel is a measure of the tendency of the fuel to resist knocking.

2008

2006

2004

  • The principle of mass spectrometry is where positive ions (charged particles) are separated (deflected, spread out)  based on (according to) relative mass(es) (charge-to-mass ratio) when moving in a magnetic field

2009

  • Nitrogen fixation is the conversion of atmospheric nitrogen to compounds which can be used by plants.

2005

  • The trapping of the sun’s energy by the atmosphere is called the greenhouse effect.

2009

Free Notes
Free Sample Answers
Statistics

Did you know?

Chemistry is more popular with girls than boys, this may be due to the fact that Medicine is more popular with girls doing their Leaving Certificate and this is reflected in the statistics below.

 

In 2011 a total of 6298 students took Chemistry at Leaving Cert .3610 girls took Chemistry at Leaving Certificate at higher level while 2688 boys did Chemistry at Higher Level in 2010.

  • 20.8% of students got an A
  • 29.3% of students got a B
  • 25.2% of students got a C
  • 16.7 % of students got a D
  • 8.1% of students failed
Exam Breakdown

Past Exam Breakdown Higher Level

Main Topics Sub-Topic 1 Sub-Topic 2 Sub-Topic 3 Sub-Topic 4    
Question 1-Atomic Structure Periodic table Energy levels and orbitals Ionisation energy Colorimeter    
Question 2-Stoichiometry Avagadro calculation pV = nRT Stoich. Calculation      
Question 3-Acids and bases Bronsted Lowry Anion tests        
Question 4-Titrations Carbonate titration Permanganate titration Thiosulphate titration Bleach titration    
Question 5-Oxidation and atmospheric Redox, O.N. & equations Ozone and CFC Greenhouse effect      
Question 6-Kinetics Factors affecting rate Rate graph Catalysis Activation energy    
Question 7-Equilibrium Le Chatelier Kc calculation Ionic equilibrium pH calculation    
Question 8-Thermochemistry Thermochem. defs. Thermochem. calc. Fuels/octane number      
Question 9-Metals Aluminium Iron        
Question 10-Nitrogen Haber & fixation Fertilisers        
Question 11-Water Hardness in water Water purification Sewage edta    
Question 12-Organic (includes hydrocarons) Nomenclature & isomers Recryst. and m.p. Prep. Ethene Prep. Ethyne    
Question 13-Organic preparations Prep. Aldehyde Prep. Acid Esters Soap    
Question 14-Physical analysis Mass spec. Chromatography Colorimeter      
             
Main Topics Sub-Topic 5 Sub-Topic 6 Sub-Topic 7 Sub-Topic 8    
Question 1-Atomic Structure Bonding E.N. and H. Bonding Shapes of molecules Crystal structure    
Question 2-Stoichiometry            
Question 3-Acids and bases            
Question 4-Titrations            
Question 5-Oxidation and atmospheric            
Question 6-Kinetics            
Question 7-Equilibrium Indicators          
Question 8-Thermochemistry            
Question 9-Metals            
Question 10-Nitrogen            
Question 11-Water Winkler          
Question 12-Organic (includes hydrocarons) React. Mechanisms Petroleum Reacts. of C=O Organic relationships    
Question 13-Organic preparations Extract clove oil          
Question 14-Physical analysis            
             
Year 2010 2009 2008 2007 2006 2005
Iron standardistation   Q1        
ethanoic titration     Q1      
sodium thiosulfate titration Q3     Q1   Q1
Water of crystallisation         Q1  
prepare ethene   Q2     Q9  
Electrolysis Q11a          
Chromatography     Q2     Q10©
steam distillation     Q2      
preparation of ethanoic acid       Q2    
Preparation of a sample of soap Q2       Q2  
Preparation of ethanal           Q2
salts   Q3     Q5(a)  Q10(a)
Radioactivity Q11b          
oil drops subatomic particle   Q4        
beta emission   Q4        
Liquefaction and Distillation of air Q11d          
Carbon Crystalline Q11c          
Heisenberg uncertainty principle   Q4     Q5(a)   
bond energy / electronegativity / chemical bonding Q10a Q4 Q5 Q4(a)©, Q5(b), Q11©B   Q5(b)&©, Q10(b)
conjugate pair bronsted lowry   Q4   Q7a Q4(e), Q5(a),Q8(b) Q8(a)(b)©
calculate PH   Q4 Q8(a) Q7b 8(aiv)  
hard or soft water Q1 Q4 Q4   Q8a  
periodic Table Q4b          
Electron Configuration Q4a          
molecular shape Q4c          
Atoms Q4d          
Combining volumes Q4e          
Activation Energy Q4f          
Covalent Bonding Q4g          
Ideal Gas Q4h          
Sewage Treatment Q4i          
Structural Formulae Q4j          
Atomic Theory Q5          
Compounds Q6          
Equilibrium balanced Equations Q7          
Acids Q8          
Reaction Q9          
Recrystallisation Q10b          
sodium dichromate Q10c          

 

Past Exam Breakdown Ordinary Level

  2010 2009 2008 2007
prepare ethyne Q1 Q1    
Prepare pure sample of sodium chloride   Q2   Q2
Titration Hydrochloric Acid Q2      
Chromatography   Q8(a) Q10(b) Q10(b)
preparation of ethanoic acid     Q1  
Preparation of a sample of soap       Q1
Determine the concentration of HCL     Q2  
salts Q3 Q8© Q3  
bond energy / electronegativity / chemical bonding   Q4(d &e), Q5 Q4(a)(b), Q5 Q4(a), Q7
Compounds Q7,Q11a      
conjugate pair bronsted lowry or arrhenius    Q10(a) Q7(a)  
calculate Define PH Q9a Q4(i), Q8(b) Q7(b) Q10(a)
hard or soft water Q4g Q9    
functional groups organic chemistry        
methane  Q4d      
UV light on Ethene or methane, Alkenes and alkanes   Q8
hydrocarbons, kerosene, petrol Q6 Q6 Q4(e),Q6 Q6
heat of formation        
water - water treatment   Q4©,Q9(b) Q8(a) Q10©
water - sewage treatment Q9b   Q8(b&c)  
BOD        
IUPAC       Q8
organic chemistry   Q7 Q9  
activation energy and effective collisions        
Oxidation        
Catalysis and catlytic converters     Q11(b)  
avogadro law and ideal gas        
calculate moles, mass or temperature and pressure, avogadro Q4(i) Q11(b)  
oxidation/ reduction in electron transfer (electrolysis)   Q11(a) Q4(g)  
isotopes        
spectrometry     Q10(b)  
Ammonia (Haber)     Q10(c)  
Free Chlorine Q10b      
Ozone, CFC, atmosphere, greenhouse   Q11©   Q11©
Hydrogen peroxide in the presence of manganese   Q3 Q10(a) Q9
heat of reaction, including experiments Q4j     Q3
nitrogen and nitrates, nitric acid        
steel / iron / metals / aluminium    Q11©b Q4(i)  
heat of combustion & combustion   Q4(f)    
equilibrium and le chatelier Q4i Q4(j), Q10(a) Q4(h),Q10©  
ionisation of water        
Steam distillation Q10c      
energy level, arrangement of atoms, bohrs       Q5, Q119
rate of chemical reaction   Q3    
sulfate/Sulphuric Acid Q10a Q8(d)    
relative atomic mass   Q10©    
radioactivity    Q10(b)    
Boyles law   Q11(b) Q11(a)  
calorimetry   Q4(b)(d)   Q4(d)
HLPC     Q10(b)  
Mendeleev     Q11(a) Q11(a)
curie   Q10(a) Q11(a) Q5(b)
Dalton   Q10(a) Q11(a) Q11(a)
Rutherford   Q10(a) Q11(a) Q5©
Hodgkin     Q11©  
Chemical Industry - case study Q11c   Q11© Q4©
Henri Becquerel       Q5(b)
Davy        Q11(a)
Greeks       Q11(a)
Faraday        Q11©
Periodic Table Q4b      
Covalent Bonds Q4c      
Fehlings Reagent Q4f      
Charles Laws Q4h      
Atoms Electronegativity Q5      
Oxygen Release as part of a reaction Q8      

 

Paper Layout

Chemistry

Marks: 400
Answer 8 / 11 Questions
Time Allocated: 3 hours

Chemistry Exam Breakdown:

 
Duration of Exam: 3 hours (180 minutes).
Total marks for exam 400 marks.
Students must answer two out of three questions from Section A and answer six questions out of 8 questions from Section B.
 
Section A
 
You must answer 2 out of 3 questions
50 Marks each
22.5 minutes
 
 
Section B
 
You must answer 6 out of 8 questions
50 Marks each
22.5 minutes 
 
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