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Sourav posted an Question
August 28, 2020 • 19:12 pm 30 points
  • IIT JAM
  • Chemistry (CY)

I solved this qs and got overall dh in kj / mole but when i put it in formula dh =du +dnrt... dh term is in kj / mole and dnrt term in kj after solving it..

How do i subtract two quantities with different units.. Plz tell me

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  • Rahul

    sorry for inconvenience that you had...I was not present to discuss your doubt....

  • Rahul best-answer

    method used by you in L.H.S. is giving correct answer sourav...and at RHSyou have not used dNg but used RT...

    cropped4852066643174373957.jpg
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    the term dnRT gives you quantity with unit Kj while the dH you got with given data is in KJ/mole.. you cannot subtract two different quantities.. plz check you did wrong

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    you are getting dU by subtracting quantity with diff units

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    to get dngRT in kj/mol..u have to take R in units kj/K/mol naa....that is 8.3/1000. then putting it in the equation we are getting answer naa..

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    look Sourav solve it..

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    just tell me the units of dH and dnRT on solving, you will see what im trying to say.. the pic you shared has both value of dh and dnRt in same units.. but here in this qs.. they are different.. just try o find out the units in the qs.

  • Rahul

    either you convert dH in joule and convert it in kJ at last or change the values of dngRT accordingly...

  • Rahul

    u have to convert them to same unit...then solve it..

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    see by doing conversion my answer is not coming

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    im not getting answers by converting units

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