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: Post your doubts here!

Discussion in 'International A And AS Level' started by XPFMember, Sep 29, 2011.

  1. MShaheerUddin

    MShaheerUddin

    Messages:
    57
    Likes Received:
    155
    Trophy Points:
    33
    Gender:
    Male
    [​IMG]
     
  2. XPC Bot

    Sponsored Listings
  3. Daveen

    Daveen

    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    1
    Hey download this app called A level chemistry by overdose
    available on playstore
     

    Attached Files:

  4. fahadhameedahmad

    fahadhameedahmad

    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    13
    Gender:
    Male
    lime stone is CaCO3
    lime is CaO or Ca(OH)2
    now all three would react with acids because acids react with carbonates (CaCO3) and bases (CaO/Ca(OH)2)

    But old lime mortar effervesces (which means produces a gas), so this would be CaCO3 as it would produce CO2 gas with HCl

    between A and D, D would be correct as water is present as well so quiklime would be Ca(OH)2
     
    MShaheerUddin likes this.
  5. Ayesha Amjad 22

    Ayesha Amjad 22

    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    1
    Gender:
    Male
    Hi Everyone I would like to post some very inportant notes for cie AS Level Chemistry. Download the notepad file. It contains the link to the website for Chemistry notes AS Levels only
     

    Attached Files:

  6. achaaa

    achaaa

    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    1
    chemhelp.PNG
    Question 2 b(iii)
     
  7. Unknown202

    Unknown202

    Messages:
    65
    Likes Received:
    4
    Trophy Points:
    18
    Gender:
    Female
    upload_2018-1-19_0-46-39.png
    someone plz solve these question answer is A
     
    Bhuvana123 likes this.
  8. Unknown202

    Unknown202

    Messages:
    65
    Likes Received:
    4
    Trophy Points:
    18
    Gender:
    Female
    upload_2018-1-19_0-51-52.png
    why ans is B plzzzzzzzzzz help
     
  9. Unknown202

    Unknown202

    Messages:
    65
    Likes Received:
    4
    Trophy Points:
    18
    Gender:
    Female
    upload_2018-1-19_0-54-28.png
    and this answer is A why?
     
  10. allexaa99

    allexaa99

    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    1
    Gender:
    Female
    First, you write out the equation

    2C3H7OH(l) + 9O2(g) -> 6CO2(g) + 8H2O(l)

    0.1 mol of propanol = 2.4dm3

    From the equation:
    2mol of propanol reacts with 9mol of oxygen
    0.1mol of propanol reacts with 0.45mol of oxygen

    0.45mol of oxygen=10.8dm3

    After the reaction,
    Since we have 12dm3 of oxygen (excess), there will be 1.2dm3 of oxygen left.
    7.2dm3 of carbon dioxide will be produced from the reaction.

    1.2+7.2=8.4dm3
     
  11. fahadhameedahmad

    fahadhameedahmad

    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    13
    Gender:
    Male
  12. fahadhameedahmad

    fahadhameedahmad

    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    13
    Gender:
    Male
  13. MShaheerUddin

    MShaheerUddin

    Messages:
    57
    Likes Received:
    155
    Trophy Points:
    33
    Gender:
    Male
    Help please.
     

    Attached Files:

  14. fahadhameedahmad

    fahadhameedahmad

    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    13
    Gender:
    Male
  15. fahadhameedahmad

    fahadhameedahmad

    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    13
    Gender:
    Male
  16. MShaheerUddin

    MShaheerUddin

    Messages:
    57
    Likes Received:
    155
    Trophy Points:
    33
    Gender:
    Male
    Sir please answer my one.
     
  17. Unknown202

    Unknown202

    Messages:
    65
    Likes Received:
    4
    Trophy Points:
    18
    Gender:
    Female
    Sir ur video are soo useful but if u can write for each question the year and paper at the title of the video rather than than at the description cuz it takes time to open each and every video to find the question u want plzz sir
     
  18. fahadhameedahmad

    fahadhameedahmad

    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    13
    Gender:
    Male
    i will change the format, question number + year in the title
    like this

     
  19. Unknown202

    Unknown202

    Messages:
    65
    Likes Received:
    4
    Trophy Points:
    18
    Gender:
    Female
    Yea but if u can also add no.of question not only year and qp plzzzz
     
  20. fahadhameedahmad

    fahadhameedahmad

    Messages:
    29
    Likes Received:
    8
    Trophy Points:
    13
    Gender:
    Male
    yes, the question number would be given at the start
     
  21. corona

    corona

    Messages:
    7
    Likes Received:
    8
    Trophy Points:
    3
    Gender:
    Male
    Location:
    Cambridge, United Kingdom
    The answer is C.

    Boron trifluoride is trigonal planar because Boron has 3 valence electrons, while the nitrogen compound is tetrahedral because nitrogen has 5 electrons and only 3 were used for bonding, leaving a pair of unbonded electrons.

    The compounds form a coordinate bond after reacting, where both the electrons from the nitrogen atom are used in forming the bond. Hence, the configuration for both sections is tetrahedral.
     
    MShaheerUddin likes this.

Share This Page