Paper 2

• Soluble substances

  Run higher up the chromatography paper
• Phases of chromatography

  • Stationary phase (the absorbent paper)
  • Mobile phase (the solvent that moves through the paper)
• Neutralization

  Reaction between an acid and a base
• Oxidation

  Gain of oxygen
• Combination

  Two or more substances combine to form a single new substance
• Combustion

  Fuel combines with oxygen
• Desalination

  The process when the dissolved mineral salts in water are removed
• Water treatment process

  1. Screening (gets rid of large objects)

  2. Sedimentation (allows solids to set at the bottom)

  3. Filtration (removes any small particles)

  4. Chlorination (removes microorganisms)
• Potable water

  Safe to drink
• Potable water is not pure water because it contains dissolved impurities
• Sewage water vs ground water

  Sewage water is harder to get to potable water than ground water because it has more bacteria and has to go through the whole process while ground water just needs to go through chlorination
• Burning fossil fuels

  Nitrogen increased and oxygen decreased
• Coal formation

  Coal plants absorbed carbon dioxide so when they died and decayed it formed coal
• Hydrocarbons

  Chemical compounds that contain the elements carbon and hydrogen only
• Pure substance

  A single substance
• Melting and boiling point

  • Can be used to find if a substance is pure because if the sample has the same melting or boiling point as the substance, then it's pure
• Alkenes

  General formula CnH2n, where n is the no. of carbon atom
• Alkanes

  General formula CnH2n+2
• Testing for alkenes

  Add a substance to bromine water and if it doesn't change colour it is an alkane and if it goes colourless it's a alkene
• Main greenhouse gases

  • Water vapour
  • Carbon dioxide
  • Methane
• High melting point

  It takes a lot of energy to break the bonds between
• Fractional distillation

  When a substance made of multiple different substances is evaporated and the different substances evaporate at different temperatures
• Crude oil is made up of multiple different substances that is formed from dead organisms from millions years ago
• Products produced from crude oil

  • Diesel fuel
  • Jet fuel
• Recycling of metal and glass

  Crushed, melted and moulded so it can be reused
• Tests for gases

  • Hydrogen - Squeaky pop test
  • Oxygen - Glowing splint
  • Carbon dioxide - Limewater
  • Chlorine - Blue litmus paper
• Formulation

  A mixture of chemicals that do not chemically react
• Examples of formulations

  • Fuels
  • Food
  • Paints
  • Medicines
• Cracking

  Hydrocarbons are heated up in order for them to break down
• Catalytic cracking

  Uses a temperature of approximately 550°C and a catalyst
• Steam cracking

  Uses a higher temperature of over 800°C and no catalyst
• Soluble

  Dissolves in water
• Insoluble

  Doesn't dissolve in water
• Renewable energy

  Can infinitely make energy without using up any resources and less harmful for the environment
• Non-renewable energy

  This is called finite, isn't infinite and will run out. Is quite harmful to the environment and causes greenhouse gases
• Renewable materials

  Won't run out because we can make more of it
• Non-renewable materials

  Will run out one day, you can't make more of it
• Earth's early atmosphere

  Had a large amount of carbon dioxide, little or no oxygen, and small amounts of other gases such as ammonia and methane
• Modern atmosphere

  Approximately 80% nitrogen, 20% oxygen, and a small amount of other gases such as carbon dioxide and water vapour
• Methane increased because of raising livestock and using landfill