1. The papers section has been updated with the latest CIE May/June 2015 resources for most of the subjects.

    Click here for more information or to discuss
    Dismiss Notice

Chemistry ATP (Important points for Both IGCSE and O-level)

Discussion in 'Cambridge O Levels' started by Nibz, May 24, 2011.

  1. Nibz

    Nibz XPC Global Moderator Staff Member

    Messages:
    4,617
    Likes Received:
    9,586
    Trophy Points:
    523
    Location:
    Old Trafford, Manchester
    Hey guys, Assalam-o-Alaikum!

    Tips for Chemistry ATP (both IGCSE and O-level):

    Some precautions:
    => Experiments involving poisonous gases like Nitrogen DIOXIDE, Ammonia and Bromine -> Carry out the exp. in Fume Cupboard or in a well Ventilated Room.
    => Experiments involving heat -> Use a polystyrene cup for insulation to prevent heat loss! + Always take the same initial readings for better accuracy;
    => Experiments involving Acids, Liquids or Solids -> Always use the same concentration; Same Volumes; Same Surface Area or Same Masses exceptions are some variables!
    => Experiment involving Crystallisation -> Allow to cool SLOWLY and Use more water and more salt for better results!
    SOME COMMON and USEFUL precautions for all experiments (use these when your mind is BLANK)
    => Repetition of the exp.
    =>Taking Average > Put your tie in shorts
    => Use Goggles
    => Taking measurements carefully and multiple measurements , to achieve accuracy ( by finding the average )
    => When drawing the best fit line in a graph , do not include points that seem to be out of the curve ,use a sharp and make the curve as smooth as possible , and remember to plot the independent Variable ( Temprature in a Time-of-reaction ( Y ) / Temprature ( X ) graph ) and NEVER forget to write the labels.

    Tests
    1.For Water:
    > By adding anhydrous Copper(II) Sulphate , which will turn from white to blue.
    > By adding anhydrous Cobalt(II) chloride , which will turn from blue to pink.

    2.For unsaturated hydrocarbon ( Alkenes )
    >Liquid : By adding Bromine water to it and shaking. (it'l go from Brown to colourless)
    >Gas : By passing the compound through Bromine water. (Colour change = Brown to colourless)

    3.For purity of substance
    Solids => Test for melting point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Ice at 0 C°
    Liquids => Test for boiling point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Water at 100 C°

    COLLECTION TECHNIQUES:
    => upward delivery is for -> gases less dense than air (Hydrogen and Ammonia)
    => Downward delivery is for -> gases more dense than air (Carbon Dioxide
    => Displacement of water method -> insoluble gases ( Methane )


    Fermentation:
    => Glucose and Yeast are used! (just rememeber that Yeat contains enzymes -> Biological Catalysts)
    => Suitable Temperature 37 degrees (Optimum for Enzyme)
    => Bung is used -> To Let Carbon Dioxide out, and prevent the entry of Oxygen.
    => Why is Oxygen's entry prevented (-> because it'l oxidize the alcohol to Carboxylic Acid and also it'l affect the anaerobic respiration)
    => Why does the reaction stop? -> Due to an excess in the conc. of alcohol, Yeast dies. Or Glucose finishes up!

    Chromatography:
    => Draw a baseline with a pencil (pencil being insoluble) about 1-2 cm above the end of the chromatogram
    => Use a pipette to put a concentrated spot of dye on the paper
    => Dip it in a solvent (Water, if it's soluble in it otherwise an organic solvent e.g Ethanol)
    => the solvent level MUST be below the baseline
    => The solvent would start to rise up the paper producing a no. of spots (depending on the no. of dyes present in the substance)
    => Spray a locating agent for colourless dyes like amino acids or simple sugars
    => Or identify with RF value (formula = (distance moved by the dye)/(distance moved by the solvent)

    Oxidising Agents!
    => KMn04 (V11) -> FROM PURPLE TO COLOURLESS!
    => K2Cr2O7 (VI) -> From Orange to Green!

    => All metals are reducing agents! (Mention the Group I metals, when asked)
    => Dehydrating Agents : Sulfuring Acid
    => Drying agent : Calcium Oxide


    Ethene test: Add bromine water and bromine water will go colourless with alkenes (ethene) and it will remain orange for alkanes (ethane)

    For precautions .. Tie your hair at the back .. Wear gloves .. Lab suit !

    Universal Indicators:
    Acid ( Red - Yellow) , Neutral ( Green) , Alkaline ( Blue - Violet)
    Phenolphthalein: Alkaline ( Pink) For Strong ( Colourless) , Neutral ( Colourless) , Acid ( Orange)
    Methyl Orange: Alkaline: ( Yellow) , Neutral ( Colourless) , Acid ( Red)
    Bromothymol Blue: Acid (Yellow) , Neutral (Dark green) , Alkaline (Blue)

    Here's a link to another great thread about ATP tips: https://www.xtremepapers.com/community/threads/chemistry-atp-tips.25439/

    Correct me where I'm wrong and also post your own tips, I will add them to my post.
    Remember me in your prayers and good luck.
     
  2. XPC Bot

    Sponsored Listings
  3. WayneRooney10

    WayneRooney10

    Messages:
    646
    Likes Received:
    40
    Trophy Points:
    38
    Gender:
    Male
    Thanks Alot. whats the test for ethene??
     
  4. HyDraZin3

    HyDraZin3

    Messages:
    169
    Likes Received:
    0
    Trophy Points:
    0
    Add bromine water and bromine water will go colourless with alkenes (ethene) and it will remain orange for alkanes (ethane)
    :D
     
  5. WayneRooney10

    WayneRooney10

    Messages:
    646
    Likes Received:
    40
    Trophy Points:
    38
    Gender:
    Male
    ahan! Thanks!
     
  6. Cozmo35d

    Cozmo35d

    Messages:
    87
    Likes Received:
    0
    Trophy Points:
    0
    Thanks Nibz :)
     
  7. skinnyboyfat

    skinnyboyfat

    Messages:
    622
    Likes Received:
    49
    Trophy Points:
    38
    Location:
    Apparently..u can only live on EARTH!!!
    Thanks...no wonder u r a global moderator...
     
  8. abcde

    abcde

    Messages:
    1,594
    Likes Received:
    485
    Trophy Points:
    93
    Location:
    Cambridge, MA
    Wonderful! Thank youu! :D
    Yes, no wonder.. He is A.M.A.Z.I.N.G. (literally)
     
  9. xIshtar

    xIshtar

    Messages:
    499
    Likes Received:
    100
    Trophy Points:
    38
    Gender:
    Male
    Location:
    Paphos, Cyprus
    Thanks for an awesome set of notes :p
     
  10. Pernee26

    Pernee26

    Messages:
    23
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Karachi Pakistan
    Awesome ! Thanks
    :)
     
  11. XPFMember

    XPFMember XPC Moderator Staff Member

    Messages:
    4,537
    Likes Received:
    13,214
    Trophy Points:
    523
    Waalaikumassalam!!

    wud like to gie a sugestion...post it as a word doc. as well..with all formatting i mean...it's more easier and better wen u see i wit different kin of colours and formatting and all tat :D

    Anyways thanks a lot! Jazak ALlah Khair!! gud work! :)
     
  12. WayneRooney10

    WayneRooney10

    Messages:
    646
    Likes Received:
    40
    Trophy Points:
    38
    Gender:
    Male
    Just copy it and paste it in a word document :D
     
  13. ajmanutd

    ajmanutd

    Messages:
    124
    Likes Received:
    0
    Trophy Points:
    16
    thanx nibz..
    this is a really gd example of a "short and sweet" set of notes..
    perfect fr last minute revision..
    thanx again.. :D :D
     
  14. cHeStEr

    cHeStEr

    Messages:
    106
    Likes Received:
    11
    Trophy Points:
    28
    Gender:
    Male
    For precautions .. Tie your hair at the back .. Wear gloves .. Lab suit ! Correction was required as for all fellow XPF people ! :)
     
    Muhammad Razi likes this.
  15. WayneRooney10

    WayneRooney10

    Messages:
    646
    Likes Received:
    40
    Trophy Points:
    38
    Gender:
    Male
    hey!! Can any one give me a list of all the indicators and how they work? Thanks.
     
  16. babyzee

    babyzee

    Messages:
    15
    Likes Received:
    0
    Trophy Points:
    0

    hey do you have business and physiics notes
     
  17. TheDealer

    TheDealer

    Messages:
    118
    Likes Received:
    30
    Trophy Points:
    28
    Gender:
    Male
    Location:
    Worldwide
    what do u mean by putting ur tie in ur shorts? :S
     
  18. TatsuEG

    TatsuEG

    Messages:
    19
    Likes Received:
    0
    Trophy Points:
    0
    To prevent your tie ( if you are wearing shorts) To catch fire , if fire is applied to an apparatus
     
  19. TatsuEG

    TatsuEG

    Messages:
    19
    Likes Received:
    0
    Trophy Points:
    0
    Alsalamalikum

    Could I ask , are the flame colours needed for Chemistry IGCSE

    Thanks :)
     
  20. abcde

    abcde

    Messages:
    1,594
    Likes Received:
    485
    Trophy Points:
    93
    Location:
    Cambridge, MA
    Umm, Nibz, nitrogen is not toxic/poisonous. Otherwise, we'll all be dead breathing 78% of nitrogen in air 24/7! :p
     
  21. Nibz

    Nibz XPC Global Moderator Staff Member

    Messages:
    4,617
    Likes Received:
    9,586
    Trophy Points:
    523
    Location:
    Old Trafford, Manchester
    Yes!! Check the attachments!

    No, they aren't!
     

    Attached Files:

Share This Page