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

    7
    ReputationRep:
    Which reaction has the largest positive value of SӨ?
    A. CO2(g) + 3H2(g)  CH3OH(g) + H2O(g)
    B. 2Al(s) + 3S(s)  Al2S3(s)
    C. CH4(g) + H2O(g)  3H2(g) + CO(g)
    D. 2S(s) + 3O2(g)  2SO3(g)

    Why is the answer C and not D? I understand the mole increases in C but in D, the state changes from solid to gas?
    Offline

    17
    ReputationRep:
    D involves 3x(g) -> 2x(g)

    Whereas C involves 2x(g) -> 4x(g)
    Offline

    9
    ReputationRep:
    (Original post by Pigster)
    D involves 3x(g) -> 2x(g)

    Whereas C involves 2x(g) -> 4x(g)
    I concur entirely.

    Entropy is in J K-1 mol-1 so the number of moles makes the difference here.
 
 
 
  • 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.