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-   -   Calculate the quantity of heat lost (https://www.askmehelpdesk.com/showthread.php?t=417372)

  • Nov 18, 2009, 11:06 PM
    sarah1004
    Calculate the quantity of heat lost
    Calculate the quantity of heat lost when 52g of S is cooled from 85C to 60C.
    The specific heat of sulfur is 0.736J/g C.

    Do I have to find mole of S first?

    Please help the step to solve this problem.Thanks
  • Nov 19, 2009, 05:56 AM
    Perito
    Quote:

    Calculate the quantity of heat lost when 52g of S is cooled from 85C to 60C.
    The specific heat of sulfur is 0.736J/g C.

    Do I have to find the number of moles of S first?

    No. You don't have to calculate the number of moles of sulfur. The reason is that your specific heat is given in Joules / (gram Celsius). If your specific heat were given in Joules/(mole Celsius), you would have to convert to moles.

    Note the units of your specific heat:

    The temperature difference is

    The weight of S is

    I've divided the temperature difference and the weight by 1 to make the following clearer:

  • Nov 19, 2009, 11:41 AM
    sarah1004
    So, this answer going to be 574.08J

    Correct?

    Thanks
  • Nov 19, 2009, 11:51 AM
    Unknown008

    No...

    What you did is only take from what Perito said. I suggest to you that you look at the explanations themselves, not the values.

    For you see, anyone can makes mistakes, and you'll see that there is an error in the calculation of the temperature change. Try again, and next time, do the work all from the start. It will be a good practice, plus it will show where you get really stuck, or even point out possible errors from our members :)
  • Nov 19, 2009, 12:00 PM
    sarah1004
    ohh okay Thanks^^
  • Nov 20, 2009, 06:09 PM
    sarah1004
    Do you know any formula for this problem?

    Thanks
  • Nov 21, 2009, 01:34 AM
    Unknown008

    It remains the same. I have already told you in previous threads:



    Q is the amount of heat involved
    m the mass involved
    c the specific heat capacity
    theta the change in temperature.

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