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Born-Haber dilema Watch

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    Hi everyone,

    I have been given the following question (all numbers are kJ/mol ):

    "Use the data below to calculate the electron affinity of chlorine":

    Standard enthalpy of atomisation of potassium 90
    First ionisation enthalpy of potassium 420
    Bond dissociation enthalpy of chlorine 244
    Lattice enthalpy of potassium chloride -706
    Standard enthalpy of formation of potassium chloride -436

    I've drawn out the Born-Haber cycle, and get a value of -484. However, the mark scheme says it's -362.

    Please can someone explain this to me?
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    Double check the value for the bond dissociation. It's usually for Cl2, and we are only dealing with Cl here. So, 244 is wrong and it has to be 122. -484+122=-362
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    (Original post by typicalvirgo)
    Double check the value for the bond dissociation. It's usually for Cl2, and we are only dealing with Cl here. So, 244 is wrong and it has to be 122. -484+122=-362
    Cool - We only started it today. Thanks for the help.
 
 
 
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