Paper 2- rate, organic, chemical, atmosphere

• Test for hydrogen


  Squeaky pop test- place burning splint in a test tube
• Test for oxygen


  Place a glowing splint in a test tube, the splint will relight
• Test for carbon dioxide 


  Gas bubbled through limewater (calcium hydroxide), turns cloudy if present
• Test for chlorine


  Turns blue litmus paper white
• Le Chatelier's principle 


  The position of equilibrium can be altered by changing the conditions of the reaction, e.g. pressure, temperature, concentration
• Complete combustion


  Enough oxygen to for a fuel to burn.

  A hydro carbon will react with oxygen to produce carbon dioxide and water

  Propane + oxygen -> carbon dioxide + water
• Incomplete combustion


  Isn't enough oxygen to burn.

  Produce water and poisonous carbon monoxide. (and soot)

  Ethane + oxygen -> carbon monoxide + water
• Alkane formula


  Cn H2n+2
• Alkene formula


  Cn H2n
• Fractional distillation definition 


  Used to separate a mixture of long chain hydrocarbons in crude oil into smaller, more useful fraction
• Fractional distillation process

  Crude oil is heated into a fractional column

  The column is hot at the bottom and colder at the top

  As crude oil evaporates it rises through the column

  These vapours condense at different fractions
• Fractional distillation explanation

  Short chain hydro carbons are found at the top of the column as they have weak intermolecular forces resulting in a low boiling point

  These leave as a gas

  Long chain hydro carbons are found at the bottom of the column and are held together by strong intermolecular forces, resulting in high boiling points
• Fractional distillation fractions

  C1 C4- liquified petrol

  C5 C9- chemicals

  C5 C10- petrol for vehicles

  C10 C16- jet fuel

  C14 C20- diesel

  C20 C50- oil

  C20 C70- fuel for ships

  >C70- bitumen for roads
• Test for alkane 


  Bromine will remain brown/orange

  Alkanes are saturated hydro carbons, they have no double bonds which could be broken to accept the bromine molecules
• Test for alkene


  Bromine will change from brown/orange to colourless, they are unsaturated hydrocarbons; the double bonds break and accept bromine molecules
• Cracking 


  Thermal decomposition reaction.

  Long chain hydro carbons are broken down into shorter, more useful hydro carbon chains.

  Produces a short chain alkane and an alkene
• Rf value (chromatography)


  distance travelled by substance/distance travelled by solvent

  Used to identify unknown substances
• Formulations 


  Mixture of compounds or substances that do not react together to produce a useful product with desirable characteristics or properties
• Chromatography- REQUIRED PRACTICAL

  Draw line 1cm from bottom of paper

  Pipette ink onto line, leave gaps

  Pour a solvent into a container just touching the bottom of the paper

  Allow solvent to move up through paper

  Before solvent reaches the top, remove paper and allow to dry

  Measure Rf value

  CV- temperature

  IV- solubility of ink

  DV- distance moved
• Factors affecting rate of reaction

  Concentration, catalysts, temperature, surface area
• Measuring the production of gas- REQUIRED PRACTICAL

  Calcium carbonate + hydrochloric acid -> calcium chloride + water + carbon dioxide

  CaCO3 + 2HCL -> CaCl2 + H2O + CO2

  Clamp gas syringe connected to a delivery tube and bung

  50ml HCL and 0.5g calcium carbonate into conical flask- immediately close with bung

  Record gas produced every 10 seconds

  Repeat with different concentrations

  Draw graph and calculate mean

  IV- Concentration

  CV- mass of calcium carbonate

  DV- gas produced
• Investigating a change in colour- REQUIRED PRACTICAL

  Sodium thiosulfate + hydrochloric acid -> sodium chloride + water + sulphur dioxide + sulphur

  Na2S2O3 + 2HCL -> 2NaCl + H20 + SO2 + S

  Black cross on white tile

  35cm Sodium thio in conical flask on white tile

  5cm water and 10cm HCL into conical flask

  record time until cross disappears

  repeat for different temperatures of Sodium thio

  DV- time

  CV- volume

  IV- temperature