Chemistry Paper 2

• Flame test result of Lithium

  Crimson
• Flame test result for Sodium


  Yellow
• Flame test result for Potassium


  Lilac
• Flame test result for Calcium


  Orange-red
• Flame test result for Copper


  Green
• Metal Hydroxide result for Copper(II)


  Blue Precipitate
• Metal Hydroxide test result for Calcium


  White precipitate
• Metal Hydroxide test result for Iron(II)

  Green precipitate
• Metal Hydroxide test result for Iron(III)

  Brown precipitate
• Magnesium - Metal Hydroxide Test Result

  White precipitate
• Aluminium - Metal Hydroxide Test Result


  White precipitate, but if there is excess NaOH it redissolves into a colourless solution
• What is meant by a pure substance?


  A substance that is only one element or compund
• What is a 'Formulation'


  A mixture precisely made, with each component in a measured quantity so that the end product can meet its required function
• 3 examples of Formulations


  Paint, Medicine and Alloys
• How can you tell is a substance is impure?


  A pure substance has an exact boiling and freezing point, unlike impure substances where there is a range of points where the substance can boil or freeze.
• Rf Value Equation


  Dist. moved by substance/ Dist moved by solvent
• Examples of the Mobile Phase


  Solvent - Liquid or Gas
• Examples of the Stationary Phase


  Paper - Solid or very thick liquid
• What does it mean if a substance spends more time in the stationary phase?


  Spending more time in a stationary phase means that they will move much slower across the paper and will move not as far.
• Method to test for Chlorine


  Have the sample gas in a test tube and place a peice of damp litmus paper into the tube The litmus paper will initially turn red as it creates HCl with the paper but then gets bleached making a white paper =
• Method to test for Oxygen


  Have the sample gas in a test tube and place a glowing splint into the tube If the splint relights
• Method to test for Hydrogen


  Have the sample of gas in a test tube and insert a lit splint into the tube A squaky pop noise will be heard
• Method to test for Carbon Dioxide


  Have the sample gas bubbled through limewater - Calcium Hydroxide If the limewater turns cloudy
• Method to test for Carbonates

  When carbonates react with acid it forms carbon dioxide along with a salt and water You can add dilute HCl to the sample and the gas produced should be bubbled through limewater If the limewater turns cloudy the sample is a carbonate
• Method to test for Sulfate


  When reacting with barium, a white precipitate is formed Add dilute HCl to remove any impurities in the sample Add barium chloride If a white precipitate is formed,
• Method to test for Halides

  Add nitric acid to remove any impurities in the sample Add silver nitrate A precipitate should form, the colour depending on the ion itself Chloride - White precipitate Bromide - Cream precipitate Iodide - Yellow precipitate
• Method of the Flame Test

  Take a platinum wire loop, and clean it by dipping it in some hydrochloric acid, rinsing it in distilled water and then heating it over a bunsen burner flame Dip the wire loop into the compound to test Hold the wire loop in the blue part of the flame See what colour the flame turns as the compound burns
• Method of the Metal Hydroxide Test

  Reach with a solution of Sodium Hydroxide, and see what colour the solution turns Some metal ions form a coloured precipetate when they react with hydroxide ions
• What is a limitation of the flame test

  If you have 2 or more different metals in your sample, the colours will mix, making it unclear what metals is in the sample
• Feedstock - The raw material used to provide reactants for an industrial reaction
• Product - The substance produced from an industrial reaction
• Reactant - The starting materials that are changed during an industrial reaction
• Petrochemical - A substance made from crude oil, via chemical reactions
• Hydrocarbon - An organic compound consisting entirely of hydrogen and carbon atoms
• Crude Oil - A mixture of many different hydrocarbons (compounds containing only carbon and hydrogen)
• Alkene - A hydrocarbon containing at least one carbon-carbon double bond.
• Alkenes when reacting with hydrogen, with the use of a catalyst makes an alkane
• Alkenes when reacting with water, with the use of a catalyst and under very high temperatures, forms an alcohol.
• Alkenes are more reactive than alkanes because they are unsaturated
• If bromine is added to an alkene, it can decolourise the orange colour unlike alkanes