Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    Please help me understan what i am supposed to do here...

    Given that

    P(g) + 3Cl(g) = PCl3(g) energy change = -983kjmol-1
    P(s) + 3/2Cl2(g) = PCl3(g) energy change = -305kjmol-1
    P(s) = P(g) energy change = +314kjmol-1

    calculate the following bond energies:

    a) P-Cl in PCl3

    b) Cl-Cl in Cl2

    i really have absolutley no idea what to do so some help would be much appreciated

    • Community Assistant
    • Study Helper
    Offline

    17
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Aleisha1)
    Please help me understan what i am supposed to do here...

    Given that

    P(g) + 3Cl(g) = PCl3(g) energy change = -983kjmol-1
    P(s) + 3/2Cl2(g) = PCl3(g) energy change = -305kjmol-1
    P(s) = P(g) energy change = +314kjmol-1

    calculate the following bond energies:

    a) P-Cl in PCl3

    b) Cl-Cl in Cl2

    i really have absolutley no idea what to do so some help would be much appreciated
    a) Look at the first equation and consider the definition of bond energy ...
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by charco)
    a) Look at the first equation and consider the definition of bond energy ...
    Hi sorry i still dont understand. i have nothing in my notes or text book telling me how to do this so i am basically starting from scratch :s
    • Community Assistant
    • Study Helper
    Offline

    17
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Aleisha1)
    Hi sorry i still dont understand. i have nothing in my notes or text book telling me how to do this so i am basically starting from scratch :s
    The bond energy is the energy required to break 1 mole of specific bonds giving gaseous atoms.

    Look again at the first equation and ask yourself "what is happening to get from reactant to products?" ...
    Offline

    7
    ReputationRep:
    (Original post by Aleisha1)
    Please help me understan what i am supposed to do here...

    Given that

    P(g) + 3Cl(g) = PCl3(g) energy change = -983kjmol-1
    P(s) + 3/2Cl2(g) = PCl3(g) energy change = -305kjmol-1
    P(s) = P(g) energy change = +314kjmol-1

    calculate the following bond energies:

    a) P-Cl in PCl3

    b) Cl-Cl in Cl2

    i really have absolutley no idea what to do so some help would be much appreciated
    What bonds (notice plural) are you forming in reaction one ? How much energy is being released to form these ? Therefore how much energy would be required to BREAK one of them ?
    Bond enthalpies are always quoted as positive as the definition is to break bonds.
    Question b you'll need to piece together reactions 2 and 3.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by charco)
    The bond energy is the energy required to break 1 mole of specific bonds giving gaseous atoms.

    Look again at the first equation and ask yourself "what is happening to get from reactant to products?" ...
    thanks i think i get it now
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Spoogle)
    What bonds (notice plural) are you forming in reaction one ? How much energy is being released to form these ? Therefore how much energy would be required to BREAK one of them ?
    Bond enthalpies are always quoted as positive as the definition is to break bonds.
    Question b you'll need to piece together reactions 2 and 3.
    thankyou very much very helpful
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 7, 2013

3,416

students online now

800,000+

Exam discussions

Find your exam discussion here

Poll
Should universities take a stronger line on drugs?

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.