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

    17
    ReputationRep:
    The equation from what I have learnt is:

    Delta H solution= Sum of delta H hydration - dHlattice formation

    I keep getting these kind of questions wrong :erm:

    E.g.

    http://qualifications.pearson.com/co...e_20140113.pdf

    Question 4
    Offline

    16
    ReputationRep:
    Do you know how to draw Hess cycles for these types of questions?



    (Original post by Dinaa)
    The equation from what I have learnt is:

    Delta H solution= Sum of delta H hydration - dHlattice formation

    I keep getting these kind of questions wrong :erm:

    E.g.

    http://qualifications.pearson.com/co...e_20140113.pdf

    Question 4
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Poooky)
    Do you know how to draw Hess cycles for these types of questions?
    Same as for any other process:

    NaCl(s) ----> Na+(aq) + Cl-(aq) ΔHsolution

    NaCl(s) ---> Na+(g) + Cl-(g) ----> Na+(aq) + Cl-(aq) (i) ΔHlattice enthalpy --- > (ii) ΔHhydration
    Offline

    16
    ReputationRep:
    (Original post by charco)
    Same as for any other process:

    NaCl(s) ----> Na+(aq) + Cl-(aq) ΔHsolution

    NaCl(s) ---> Na+(g) + Cl-(g) ----> Na+(aq) + Cl-(aq) (i) ΔHlattice enthalpy --- > (ii) ΔHhydration
    I was trying to get OP to work through it I thought if she could draw it out, she'd be able to see where she went wrong- usually it's either using the wrong signs or forgetting about balancing the equation ie that there are 2 Cl-'s involved in the reaction- hopefully that helps Dinaa
    • Community Assistant
    • Study Helper
    Offline

    15
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Poooky)
    I was trying to get OP to work through it I thought if she could draw it out, she'd be able to see where she went wrong- usually it's either using the wrong signs or forgetting about balancing the equation ie that there are 2 Cl-'s involved in the reaction- hopefully that helps Dinaa
    I'm sorry, I misread your post ...
 
 
 
    Discussions on TSR

  • Latest
  • Personalise
Poll
Who is your favourite TV detective?

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

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