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Homework Help: 10 gal of Jell-O

  1. Sep 22, 2005 #1
    As I am actually performing this, it occurred to me I'm a bit rusty and cannot define the formula to calculate the following process. Anyone who can solve this and show a proof, your help would be appreciated. NO, I'm not a student looking for someone to do my work, I've been out of school for 7 years..... which is why I'm rusty.

    10 US gal of a solution is made using 5 gal of boiling water, added to 5 gal of a solution (which is 99% water).
    These 10 gal are then placed in an empty locker freezer, which is approx 10 cubic ft, and has an ambient temp of -10 degrees(F).

    My question is: how long should it take to cool the solution to 35 degrees(F)?
    I have not been able to figure out cold output of the freezer, so answer would have to use a variable to define the strength of the freezer's output in the formula for "t".

    Thanks in advance.
     
  2. jcsd
  3. Sep 22, 2005 #2

    FredGarvin

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    Science Advisor

    Without going into a huge heat transfer analysis, I'd estimate it using Newton's law of cooling:

    [tex]q = m C_p \Delta T[/tex]

    The only thing you'll have to do is to use a bit of chemistry to calculate the specific heat of the mixture. Once you know that, you need the capacity of the freezer in some units along the lines of btu/min to calculate the time necessary.
     
    Last edited: Sep 22, 2005
  4. Feb 10, 2010 #3
    Hello,

    I am a student doing a science project where I need to know the specific heat of Jell-O. I googled "specific heat of Jell-O" and this thread came up. Sorry to be a bit random, but do you know the specific heat of Jell-O? It would help me immensely, as I have not had enough schooling yet to know how to calculate this.

    Thank you,

    A middle school student
     
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