Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    13
    ReputationRep:
    Q. Which of the following letters corresponds to the number of moles of each element in 53g or Na2CO3 (Mr: 106)

    *A: Na 0.5 / C 0.5/ O 0.5
    *B: Na 1 / C 0.5/ O 3
    *C Na 1/ C 0.5/ O 1.5

    Mark scheme answer is C but I need an explanation please
    Offline

    2
    ReputationRep:
    (Original post by valbrechts)
    Q. Which of the following letters corresponds to the number of moles of each element in 53g or Na2CO3 (Mr: 106)

    *A: Na 0.5 / C 0.5/ O 0.5
    *B: Na 1 / C 0.5/ O 3
    *C Na 1/ C 0.5/ O 1.5

    Mark scheme answer is C but I need an explanation please
    First calculate the number of moles of the compound: 53/106 = 0.5 moles of Na2CO3

    Remember a mole is just a number. So if one molecule contains 2 sodium atoms, then 0.5 moles should contain 2*0.5 = 1 mole of sodium atoms.

    Can you do the rest now?
    Offline

    1
    ReputationRep:
    does anyone know part 3 (a) (iii)? I don't know why they divided it? thanks
    Offline

    3
    ReputationRep:
    (Original post by ruchitax)
    does anyone know part 3 (a) (iii)? I don't know why they divided it? thanks
    Post the question
    Offline

    1
    ReputationRep:
    (Original post by Squishy•)
    Post the question
    http://filestore.aqa.org.uk/subjects...W-QP-JUN10.PDF
    forgot to send the link. that is the paper.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Brussels sprouts
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.