C3: PART TWO

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  • C3: PART TWO
    • TITRATIONS
      • 1) add known volume of alkali into flask 2) add indicator (not universal tho) 3) pour acid in burette and take reading 4) open tap, add acid until solution is neutral          5) repeat 3 times and then once without indicator
      • 1 decimentre^3 is 1000cm^3 cubed. Concentration is measured in moles per dm^3. The mass (g) of one mole is it's relative formula mass.
    • PURIFYING WATER
      • Using appropriate source, eg reservoir. screens (remove debris), settlement tank (sand ect) , aluminium sulfate (dirt clumps), filter (removes insoluble solid remainders), chorine (kill bacteria).
      • 1.screens 2.settlement tank 3.aluminium sulfate 4.filter 5.flourine
    • MAKING AMMONIA (CONDITIONS)
      • nitrogen and hydrogen combine in an IRON catalyst to produce ammonia. Pressure: 200 atmospheres. Temperature: 450^C.
      • reaches a point where the rate of reaction on both sides has reached EQUILIBRIUM. this means the amount of ammonia produces is equal to amount a nitrogen and hydrogen.
        • increase in pressure favours the direction of reaction that produces the LEAST number of molecules.
        • Forward reaction is exothermic. Increase in temperature increases endothermic reaction, creating a lower yield of ammonia produced.
      • TIPS: don't confuse rate of reaction with yield. how pressure effects yield of ammonia. conditions are compromised between yield, rate and cost.
    • MAKING AMMONIA
      • Used to make fertiliser. Also makes household cleaners. NITROGEN + HYDROGEN >< AMMONIA
      • Need Nitrogen (from air) and Hydrogen (from methane) to produce a liquefied ammonia (condensing).
      • iron catalyst, pressure at 200 atmospheres, temperature at 450^C. Increases rate of reaction and the yield.
    • ORGANIC COMPOUNDS
      • organic compounds are the basis of all living things, and contain carbon. The 3 main organic compounds are alcohols, esters and carboxylic acids.
        • CARBOXYLIC ACIDS have a functional group of COOH. Methanoic acid, ethanoic acid and propanoic acid.
        • ESTERS have functional group COO. Evaporate easily. Smell and taste fruity. Made by alcohol+ carboxylic acids.
    • TEST FOR POSITIVE AND NEGATIVE IONS.
      • POSITIVE: flame test. crimson is lithium, yellow is sodium, lilac is potassium, red is calcium and green is barium.
      • POSITIVE: sodium hydroxide. get either white or coloured precipitate. White dissolves is aluminium. White doesn't dissolve is magnesium or calcium.
        • coloured precipitates: brown is iron3+, green is iron2+, blue is copper.
      • NEGATIVE: add dilute acid to a carbonate (should fizz). HALIDES: dilute nitric acid -> silver nitrate -> precipitate formed.
    • HYDROGEN AS A FUEL. currently use petrol, diesel and ethanol, contribute to pollution. Hydrogen only produces H2O. They're expensive and unsafe (at a very high pressure).
  • Ethanoic acid ionises -> only some of it ionises -> reversible reaction -> lower concentration of H+.

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