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-   -   Find kilojoules (https://www.askmehelpdesk.com/showthread.php?t=439227)

  • Jan 25, 2010, 09:55 PM
    hslove142331
    Find kilojoules
    The molar heat of vaporization of carbon disulfide, CS2, is 28.4 kJ mol-1 at its boiling point. How many kilojoules of heat would be liberated by the condensation of 6.57 g of carbon disulfide?

    How can I find kilogules?
    Any equations?

    Thank you..
  • Jan 26, 2010, 08:10 AM
    Unknown008

    The compiound takes 28.4 kJ/mol on boiling.

    Therefore, it releases 28.4 kJ/mol on condensing. (reverse process)

    Find the number of moles you have in 6.57 g and use proportions to find the heat release upon condensation.
  • Jan 27, 2010, 02:29 PM
    hslove142331
    I got 11.56moles... and how can I do next?
  • Jan 28, 2010, 07:08 AM
    Unknown008

    1 mole of CS2 weighs (12+32+32) = 76 g

    Or;
    76 g of CS2 contains 1 mole.
    1 g of CS2 contains 1/76 mole
    6.57 g of CS2 contains (1/76)*6.57 = 0.0864 mol

    Now, 1 mole releases 28.4 kJ
    0.0864 mol will release (28.4*0.0864) = 2.46 kJ.

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