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  • Moderator
    Darkness_hacker99
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    31,746 posts since Jun '05
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    Darkness_hacker99
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    31,746 posts since Jun '05
  • thehappybunny
    thehappybunny's Avatar
    5,582 posts since Aug '07
    • 24 Oct `07, 5:10PM

      easy paper, only got some careless mistake here and there, like the one with ethanoic acid react with calcium carbonate, i forgot about CH3COO- (-ve charge) and that is Ca(CH3COO)2

      zzz

      then got the one about salt conducting electricity, its supposed to be mobile IONS and not mobile ELECTRONS.

      zzz

      other than that, easy paper

  • masterofIT
    masterofIT's Avatar
    53 posts since Jun '07
    • 24 Oct `07, 5:10PM

      Hoho. Paper was damn easy. But well, guess moderation will pull up the A1 grade again. Let's say...A1= 80%?!

      LOL.

  • masterofIT
    masterofIT's Avatar
    53 posts since Jun '07
    • 24 Oct `07, 5:13PM

      Originally posted by thehappybunny:
      easy paper, only got some careless mistake here and there, like the one with ethanoic acid react with calcium carbonate, i forgot about CH3COO- (-ve charge) and that is [b]Ca(CH3COO)2
      zzz

      then got the one about salt conducting electricity, its supposed to be mobile IONS and not mobile ELECTRONS.

      zzz

      other than that, easy paper
      [/b]

      huh?! That's the ans? (salt)

  • rain-coat
    rain-coat's Avatar
    492 posts since Sep '07
    • 24 Oct `07, 5:17PM

      the part about methane and pollution problem, what is it?

      Global warming is NOT a pollution.

      Overall is was quite ok. Very Happy

  • rain-coat
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    492 posts since Sep '07
    • 24 Oct `07, 5:18PM
      Originally posted by thehappybunny:
      easy paper, only got some careless mistake here and there, like the one with ethanoic acid react with calcium carbonate, i forgot about CH3COO- (-ve charge) and that is Ca(CH3COO)2

      zzz

      then got the one about salt conducting electricity, its supposed to be mobile IONS and not mobile ELECTRONS.

      zzz

      other than that, easy paper

      i wrote ionic eqn leh cos i don know how to write e full eqn. so correct or wrong?

  • thehappybunny
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    5,582 posts since Aug '07
    • 24 Oct `07, 5:19PM
      Originally posted by masterofIT:
      huh?! That's the ans? (salt)

      yeah, according to my friends thats the answer, but some of them cant balance the eqn. since its a metal carbonate, there will be salt, water and carbon dioxide

  • masterofIT
    masterofIT's Avatar
    53 posts since Jun '07
    • 24 Oct `07, 5:24PM
      Originally posted by thehappybunny:
      yeah, according to my friends thats the answer, but some of them cant balance the eqn. since its a metal carbonate, there will be salt, water and carbon dioxide

      Lol. I didn't balanced it either. 2 marks gone.

  • masterofIT
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    53 posts since Jun '07
    • 24 Oct `07, 5:26PM

      Methane ah.. i wrote something like that. My friends say methane has a variety of answers and that cambrige won't be that strict when it comes to marking.

      Methane, source -> decomposition of baterial matters.
      Methane, pollution -> methane will lead to greenhouse warming which will increase the global temperature.

      Weak ans though. Lol.

  • thehappybunny
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    5,582 posts since Aug '07
    • 24 Oct `07, 5:27PM

      lol. i thought methane was a natural gas then i put the source of methane as 'Farms.'

      Rolling Eyes

  • rain-coat
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    492 posts since Sep '07
    • 24 Oct `07, 5:31PM

      Green house gases is pollution meh? i wrote incomplete combustion of methane produces pollutants

  • lolhahalol
    lolhahalol's Avatar
    29 posts since Jul '07
    • 24 Oct `07, 5:39PM
      Originally posted by thehappybunny:
      easy paper, only got some careless mistake here and there, like the one with ethanoic acid react with calcium carbonate, i forgot about CH3COO- (-ve charge) and that is Ca(CH3COO)2

      zzz

      then got the one about salt conducting electricity, its supposed to be mobile IONS and not mobile ELECTRONS.

      zzz

      other than that, easy paper

      isnt it (CH3COO)2Ca

  • ultranova3
    ultranova3's Avatar
    128 posts since Aug '07
    • 24 Oct `07, 6:36PM
      Originally posted by rain-coat:
      Green house gases is pollution meh? i wrote incomplete combustion of methane produces pollutants

      Incomplete combustion of methane???
      Produce pollutant???

      CH4 + 2O2 --> CO2 + 2H2O

      methane almost always undergoes complete combustion. No pollutant except CO2.

  • SBS 233 X
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    1,987 posts since Aug '05
  • Moderator
    Darkness_hacker99
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    31,746 posts since Jun '05
    • 24 Oct `07, 6:40PM
      Originally posted by ultranova3:
      Incomplete combustion of methane???
      Produce pollutant???

      CH4 + 2O2 --> CO2 + 2H2O

      methane almost always undergoes complete combustion. No pollutant except CO2.

      Incomplete combustion also produce Soot(Unburnt Carbon) and Carbon monoxide.

  • ultranova3
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    128 posts since Aug '07
    • 24 Oct `07, 6:49PM
      Originally posted by Darkness_hacker99:
      Incomplete combustion also produce Soot(Unburnt Carbon) and Carbon monoxide.

      What will be the equation??

      CH4 + O2 --> C + 2H2O???
      CH4 + O2 --> CO + H2O ???

      It is very unlikely, even in limited oxygen for methane to burn incompletely.
      Those that usually undergoes incomplete combustion are those with long carbon chain. Some more CH4 is a gas and highly flammable.

      Btw, methane can trap IR and contribute to global warming.

  • limywv
    limywv's Avatar
    935 posts since Dec '06
    • 24 Oct `07, 6:51PM
      Originally posted by lolhahalol:
      isnt it (CH3COO)2Ca

      yes you are right, i also put that as my answer, i intentionally placed the cation at the back because if you understand the concept, it is supposed to be placed at the back.

  • Lin Yu
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    2,892 posts since Jul '07
  • stellazio
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    45,083 posts since Apr '05
  • lpx88
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    6,985 posts since Jun '05
  • mrcoconut
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    650 posts since May '07
  • Moderator
    eagle
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    17,966 posts since Aug '01
    • 24 Oct `07, 8:15PM
      Originally posted by mrcoconut:
      knnn, but really ah

      why today's paper so easy?

      i was expecting a much harder one

      easy ppl complain
      hard parents complain

      Sgreans just like to complain

  • hisoka
    hisoka's Avatar
    33,063 posts since Mar '05
    • 24 Oct `07, 9:19PM
      Originally posted by eagle:
      easy ppl complain
      hard parents complain

      Sgreans just like to complain

      it really depends on who's perspective you are taking. If you are a good student(as in good at your studies) you want hard papers otherwise every one gets high marks and you cannot excel.

      on the other hand, the average and lousier students want easier papers so that they can get confused with the good ones
      Laughing Laughing

  • Lin Yu
    Lin Yu's Avatar
    2,892 posts since Jul '07
    • 24 Oct `07, 9:23PM
      Originally posted by hisoka:
      it really depends on who's perspective you are taking. If you are a good student(as in good at your studies) you want hard papers otherwise every one gets high marks and you cannot excel.

      on the other hand, the average and lousier students want easier papers so that they can get confused with the good ones
      Laughing Laughing

      wan easy...so everybody can pass Laughing Laughing Laughing

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