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

    13
    ReputationRep:
    I'm completing an ideal gas equation question and I'm unsure regarding the moles of gas produced and which number of moles to use in the question.
    The moles use in the mark scheme is the total moles of gas divided by 2, times the moles of magnesium nitrate but I am unsure why they have done this. Please could anyone explain with what is the number of moles that you would substitute into your equation?

    I have attached both the question from the exam paper and the mark scheme
    Attached Images
      
    Offline

    17
    ReputationRep:
    2 mol of Mg(NO3)2 turns into 5 mol of gas (4 mol of NO2 + 1 mol of O2). Therefore x mol of Mg(NO3)2 will turn into 5x/2 mol of gas.

    The Q asks about the total volume of gas, NOT the total volume of one of the gases e.g. of O2.
    Offline

    17
    ReputationRep:
    (Original post by jazz_xox_)
    I'm completing an ideal gas equation question and I'm unsure regarding the moles of gas produced and which number of moles to use in the question.
    The moles use in the mark scheme is the total moles of gas divided by 2, times the moles of magnesium nitrate but I am unsure why they have done this. Please could anyone explain with what is the number of moles that you would substitute into your equation?

    I have attached both the question from the exam paper and the mark scheme
    It's because there is 5/2 times the number of moles of gas produced compared to the number of moles of magnetism nitrate in the reaction equation
 
 
 
  • 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.