Chemistry Study Notes
Junior Cert Science

Here is a summary of the main concepts that you need to know for each of the Junior Cert Chemistry chapters (as laid out in EDCO's Exploring Science. There are also examples of mindmaps created by students in St Colmcille's CS. Feel free to look at these mindmaps but remember that the learning happens when you make your own.

Underlined concepts are higher level only.

17 - Solids, liquids and gases

  • ​OC1   Name three states of matter and know their characteristics

18 – Solutions & Crystallisation

  • OC15    Investigate the solubility of a variety of substances in water and the effect of temperature on solubility
  • OC16    Examine the difference between a dilute, concentrated and saturated solution
  • OC17     Grow crystals using alum or copper sulphate

19 – Separating Mixtures

  • OC2     Separate mixtures using a variety of techniques: filtration, evaporation, distillation and paper chromatography
  • OC32     Carry out a simple distillation, and obtain a sample of water from sea-water

​20 – Elements, Compounds & Mixtures

  • OC3   Understand what an element is and recall that all known elements are listed in the Periodic Table; understand what a compound is and what a mixture is; recall that when elements combine to form compounds they may lose their individual properties
  • OC4   Examine a variety of substances and classify these as elements or compounds (using the Periodic Table as a reference)
  • OC12   Compare the properties of the simple compounds H2O, CO2, MgO and FeS to those of the constituent elements
  • OC13   Compare mixtures and compounds made from the same constituents, and understand that an alloy is a mixture

21 – The Atom

  • OC39     Describe the structure of the atom, state the location, relative charge, and atomic mass of the sub-atomic     particles, and define atomic number and isotope
  • OC40     Draw the Bohr structure of the first 20 elements

22 – Periodic Table

  • OC48     Describe the general properties of the alkali metals and understand that alkali metals are in Group I of the Periodic Table and have similar properties
  • OC49     Describe the reactions of the alkali metals with air and water (word equations for reaction with water)
  • OC50     Understand that Group II elements are the alkaline earth metals

23 – Chemical Bonding

  • OC41     Understand how atoms of elements combine to form compounds
  • OC42     Recall that ionic bonding is an attraction between positive and negative ions; describe the bonding in NaCl and MgO as examples
  • OC43     State what a molecule is, understand that covalent bonds involve the sharing of pairs of electrons, and describe the bonding in H2, O2, H2O, CH4 as examples of covalent bonding
  • OC44     Investigate the ability of ionic and covalent substances to conduct electricity

24 – Metals & Non-Metals

  • OC4     Examine a variety of substances and classify these as metals or non-metals
  • OC5     List the physical properties (state and colour only) of two examples of metallic and two examples of non-    metallic elements
  • OC6     Recall that metals conduct electricity and heat
  • OC7     Identify everyday applications of metals, for example in industry, in the making of jewellery
  • OC8     Recall the symbols of the metallic elements Cu, Zn, Al, Fe, Ag, and Au
  • OC9     Recall the symbols of the non-metallic elements C, O, S, H and N
  • OC10     Understand that metals are shiny (lustrous), can be beaten into shape (malleable) and can be stretched (ductile)
  • OC11     Understand that solder, steel, brass and bronze are alloys, and state one use of each alloy
  • OC45     Understand that rusting is a chemical process that changes iron into a new substance
  • OC46     Carry out an experiment to demonstrate that oxygen and water are necessary for rusting
  • OC47     List three examples of methods of rust prevention: paint, oil, galvanising
  • OC51     Investigate the reaction between zinc and HCl, and test for hydrogen (word equation and chemical equation)
  • OC52     Investigate the relative reactivities of Ca, Mg, Zn, and Cu based on their reactions with water and acid (equations not required)

25 – Fossil Fuels

  • OC53     Recall that fossil fuels are sources of hydrocarbons, and that they produce CO2 and H2O when burned
  • OC54     List two examples of fossil fuels
  • OC55     Describe the role of the combustion of fuels and of SO2 in the production of acid rain, and describe the effects of acid rain
  • OC56     Describe the effect of acid rain on limestone and on plants
  • OC57     Understand that natural gas is mainly methane

26 – Acids & Bases

  • OC18     Use litmus or a universal indicator to test a variety of solutions, and classify these as acidic, basic or neutral
  • OC19     Investigate the pH of a variety of materials using the pH scale
  • OC20     Give examples of everyday acids and bases.
  • OC35     State the names and formulae of common strong acids and bases: H2SO4, HCl, NaOH, Ca(OH)2, and     understand that alkalis are soluble bases
  • OC36     Show the neutralisation of an acid with a base using an indicator
  • OC37     Understand that, when an acid reacts with a base, a salt and water are formed
  • HCl + NaOH → NaCl + H2O (word equation O.L.)
  • 2HCl + CaCO3 → CaCl2 + CO2+ H2O (word equation O.L.)
  • OC38     Titrate HCl against NaOH, and prepare a sample of NaCl.

27 - The Atmosphere

  • OC21   Understand that air is a mixture of gases, and state the composition of air (approximately 78% N2 and 21% O2, with CO2, water vapour and other gases making up the balance)
  • OC22   Show that approximately one fifth of the air is oxygen; show that there is CO2 and water vapour in air
  • OC23   Demonstrate and describe what happens when (i) a wooden splint and (ii) a piece of magnesium are burned in air
  • OC24   Prepare a sample of oxygen by decomposing H2O2 using MnO2 as a catalyst (word equation and chemical equation)
  • OC25   Investigate the ability of oxygen to support combustion in a wooden splint and a candle, and state two uses of oxygen
  • ​OC26   Burn carbon and magnesium in oxygen, and test the products using moist litmus paper
  • OC27   Prepare carbon dioxide (word equation and chemical equation), and show that it does not support combustion
  • OC28   Carry out simple tests on carbon dioxide involving its reaction with limewater (word equation and chemical equation), and with moist litmus paper
  • OC29   Investigate the density of carbon dioxide relative to air (qualitative only), and state two uses of carbon dioxide

28 - Water

  • OC14     Use cobalt chloride paper or anhydrous copper sulfate to test for water
  • OC33     Describe the processes involved in the treatment of water supplied to domestic consumers
  • OC34     Investigate the de-composition of water by electrolysis; recall the composition of water

29 – Water Hardness

  • OC30     Conduct a qualitative experiment to detect the presence of dissolved solids in water samples, and test water for hardness (soap test)
  • OC31     Understand that some dissolved compounds, including compounds of calcium, cause hardness in water, and that water hardness can be removed using an ion-exchanger

30 - Plastics

  • OC58     Identify everyday applications of plastics, and understand that crude oil products are the raw material for their production
  • OC59     Relate the properties of plastics to their use
  • OC60     Describe and discuss the impact of non-biodegradable plastics on the environment​ 
  • OC61     Understand that chemistry has an important role in pharmacy, medicine and the food industry.