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Topic: Final temperature of a mixture  (Read 4788 times)

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Offline oceanmd

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Final temperature of a mixture
« on: April 17, 2008, 11:13:53 PM »
Please check the problem below and explain if it is wrong. Thank you.

What is the final temperature of a mixture of chromium metal when 50.0 grams of chromium at 15 degrees C ( specific heat = 0.448 J/g C) is added to 25 mL of water (specific heat = 4.18 J/ g C) at 45 degrees C?

This is what I think.  0.448 x 50 x (x-15) = -(4.18 x 25 x (x-45)), the answer is 40 degrees C

I need the minus before the second part of the equation because water releases heat, so the number is negative, and to make the equation work I need minus. Is this correct? Is there a better explanation?

Thank you

Offline phmonkey

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Re: Final temperature of a mixture
« Reply #1 on: April 18, 2008, 02:03:47 AM »
0.448 x 50 x (x-15) = -(4.18 x 25 x (45-x)),
i believe its that, because 45 degrees is going down

Offline phmonkey

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Re: Final temperature of a mixture
« Reply #2 on: April 18, 2008, 02:07:11 AM »
i switched x and 45 around in case u didnt see it

Offline ARGOS++

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Re: Final temperature of a mixture
« Reply #3 on: April 18, 2008, 03:44:29 AM »
Dear Phmonkey;

The swap of x and 45 you did correct.

0.448 x 50 x (x-15) = -( 4.18 x 25 x (45-x) )
But do you really believe that now both are required?

Good Luck!
                    ARGOS++
Formulas, in its best sense,  ARE ONLY Recipes for “A Picture”,  —
     If you DON’T catch “The Picture”, you are lost, - for ever!      (A++)

There is ONLY one correct Formula for the “Hydrogen”:  —
     The Atom/Molecule, ITSSELF!                          (Dr. R. Mory  1968)

"Make it AS SIMPLE AS possible,  — BUT NEVER SIMPLER!"  (A. Einstein)

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