GCE O Level Chemistry Aftermath Report

• Occam's Razor

  20 Oct 08, 17:22

  it is titration see my above post (edited)

• XxHoWxX

  20 Oct 08, 17:22

  I type out my ans la for Qn 10.

  Warm some sulphuric acid. Place excess sodium carbonate into acid. Stir the acid. Filter the mixture. Take the filtrate and place it in an evaporating dish. Heat till 1/3 of the filtrate is left. Let the solution to cool. Dry the crystals between sheets for filter paper. Sodium Sulphate crystals is then obtained.

• deteq

  20 Oct 08, 17:24

  Originally posted by gunner77:

  i wrote 2.01 tonnes. i never round off to 2.02

  question2 part a is wat?

  u mean the name a element from group I and VI

  i put sodium and sulphur.

  Na2SO4

  na2so4. but u put sodium and sulphur how come can have O inside.

• gunner77

  20 Oct 08, 17:25

  the O belong to the S wat

• Occam's Razor

  20 Oct 08, 17:27

  eg. grp 1 element     sodium
  
  grp VI element   sulphur
  
  formula ---> Na2S   (no O)

• gunner77

  20 Oct 08, 17:28

  wah lao

  wrong liao

• gunner77

  20 Oct 08, 17:28

  thought its sodium + sulphur = sodium sulphate?

• Ah sian

  20 Oct 08, 17:30

  Originally posted by XxHoWxX:

  I type out my ans la for Qn 10.

  Warm some sulphuric acid. Place excess sodium carbonate into acid. Stir the acid. Filter the mixture. Take the filtrate and place it in an evaporating dish. Heat till 1/3 of the filtrate is left. Let the solution to cool. Dry the crystals between sheets for filter paper. Sodium Sulphate crystals is then obtained.

  thought is crystailation why ppl say titration

• XxHoWxX

  20 Oct 08, 17:31

  i also think its crystalisation

  My Q2 only can get 1 mark for part a cos i wrote grp 7

• Occam's Razor

  20 Oct 08, 17:32

  sodium + sulphur = sodium sulphide
  
  
  starting material: sodium carbonate + an acid (dilute sulphuric acid)  --> to get: sodium sulphate crystals
  
  it is titration because sodium carbonate is soluble so we cant use the crystallisation/general method to obtain pure crystals.
  
  soluble so cant see how much is used up and cant filter away. therefore titration is the only way.

• Maith

  20 Oct 08, 17:33

  crystallisation

• Ah sian

  20 Oct 08, 17:37

  arrrrrr any wan for this forum to remember my login and how show quote why they always hide one

• MyPillowTalks

  20 Oct 08, 17:37

  gg

  i ssay sodium nitrate and sulphuric acid

• Ah sian

  20 Oct 08, 17:41

  fail o level liao la ccb diu la one year gone liao

• gunner77

  20 Oct 08, 17:42

  Originally posted by Ah sian:

  fail o level liao la ccb diu la one year gone liao

  
  x2

  die liao

  should not have come sec 5

• Ah sian

  20 Oct 08, 17:43

  how many mark was the paper

• gunner77

  20 Oct 08, 17:45

  65 mark

  my essay also gone.

  knn.

• SBS1984E

  20 Oct 08, 17:45

  who taking Syllabus 5072?

• Ah sian

  20 Oct 08, 17:45

  i sec 4 leh

  my school say i fail o and is at my own risk leh

  fail liao no where to go

• Ah sian

  20 Oct 08, 17:46

  Originally posted by gunner77:

  65 mark

  my essay also gone.

  knn.

  what essay

  wa u so smart take pure

• Maith

  20 Oct 08, 17:47

  i sure pass. B3 somemore 

• Garrick_3658

  20 Oct 08, 17:48

  Originally posted by SBS1984E:

  who taking Syllabus 5072?

  I am. That has got to be the easiest practice paper I have ever done in my Chemistry life in school.
  
  
  
  
  
  
  
  Wait, it was O level?

• gunner77

  20 Oct 08, 17:48

  Originally posted by Ah sian:

  what essay

  wa u so smart take pure

  
  not pure la

  the combined sci

  the behind is call structure essay wat

• tinuviel07

  20 Oct 08, 17:49

  Originally posted by gunner77:

  the tonnes one tin tin got teach me !!

  but i no time to slowly tink and do, at the end i just whack the answer as 2.01tonnes.

  

  
  you good hor.. still dare to say that.. tsk

• gunner77

  20 Oct 08, 17:50

  Originally posted by tinuviel07:

  
  you good hor.. still dare to say that.. tsk

  
  the ans is 2.02 tonnes leh

  i forgot to round off!!

  wah lao i do at the last min somemore i never show my working clearly.

  but when i do tat question i tink of u liao

  tat cake got 10kg then chocolate