Card Set Information

2011-10-20 16:52:20

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  1. using sodium carbonate to standardise HCL
    • methyl orange indicator.. yellow -> faint pink
    • indicators are slighty acidic so dont use too much
  2. primary standard
    sodium carbonate
  3. sodium hydroxide
    causes burns
  4. sodium hydroxide and HCL
    methyl orange, yellow->red
  5. % ethanoic acid in vinegar
    • phenolphthalein... pink ->colourless
    • (weak acid strong base)
  6. % water crystallisation in hydrated sodium carbonate
    methyl orange... yellow -> pink
  7. halogens
    acts as oxidising agents because high electronegativity values
  8. ammonium iron(II)sulfate and KMnO4
    • >add dilute sulphuric acid at start to prevent hydrolis (Fe2+ -> Fe3+)
    • >add before titration to provide H+ ions, stop MnO2 forming, dark brown ppt
    • >no indicator needed.. faint perm. pink
    • >read from top.. intense colour
  9. amount of iron in tablet
    • iron(II)sulfate and KMnO4
    • add dilute sulphuric acid
    • acts as own indicator
    • stains glassware
  10. sodium thiosulphate and iodine
    • add dilute sulphuric acid.. liberates iodine (brownish/red)
    • titrate until pale yellow.. add starch indicator.. blue/black.. titrate until colourless
  11. iodine
    not primary standard... vapourises at room temp.. polar
  12. %(w/v) of sodium hypochlorite in household bleach
    • >dilute bleach.. otherwise large amount of thiosulphate would be needed
    • >bleach in conical flask.. add sulphuric acid and potassium iodine
    • >dilute sulphuric acid.. liberates iodine (reddish/brown colour)
    • >titrate.. pale yellow.. starch indicator.. blue/black.. colourless
  13. using pipette
    • 1.rinse with deionised water,
    • 2.rinse with liquid thats to go in it,
    • 3.use pipette filler, measure 25cm3,
    • 4.bottom of meniscus on line at eye level,
    • 5.hold upright and allow it to drain,
    • 6.touch tip of pipette on inside of conical flask
  14. diluting
    • 1.pipette in solution
    • 2.add deionised water until below mark
    • 3.level surface.. get down to eye level.. use wash bottle of deionised water and fill until bottom of meniscus at mark
    • 4.stopper and invert 20 times
    • 5.label
  15. using a burette
    • 1.wash with deionised water
    • 2.rinse with solution
    • 3.allow rinsed solution to run through
    • 4.using funnel fill burette with solution to above the zero mark.. remove funnel
    • 5.open tap and allow area below tap to fill
    • 6.close tap when bottom of meniscus at zero
    • 7.make sure it clamped safely and upright
  16. conical flask
    • 1. shaped for convience of stirring and shaking.. no spilling
    • 2. sides can be washed down with deionised water at any time
    • 3.this will dilute solution but not change the number of moles of solution measure in it