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

    1
    ReputationRep:
    Hi, I need some help with this question:

    3.00g of lawn sand containing an iron(II) salt was shaken with dilute H2SO4. The resulting solution required 25cm3 of 0.2moldm-3 potassium manganate(VII) to oxidise the Fe2+ ions in the solution to Fe3+ ions. Use this to calculate the percentage by mass of Fe2+ ions in this sample of of lawn sand.

    I've been able to find the number of mols in the iron salt solution, however I don't know what to do next seeing as there is no volume for me to work out the concentration.
    • Community Assistant
    Offline

    15
    ReputationRep:
    (Original post by Umi-chan)
    Hi, I need some help with this question:

    3.00g of lawn sand containing an iron(II) salt was shaken with dilute H2SO4. The resulting solution required 25cm3 of 0.2moldm-3 potassium manganate(VII) to oxidise the Fe2+ ions in the solution to Fe3+ ions. Use this to calculate the percentage by mass of Fe2+ ions in this sample of of lawn sand.

    I've been able to find the number of mols in the iron salt solution, however I don't know what to do next seeing as there is no volume for me to work out the concentration.
    What is the mass of the Fe(II) ions present? You should be able to find the percentage from there.
 
 
 
  • 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
    What newspaper do you read/prefer?
  • 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.