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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: soaring206 on December 08, 2004, 08:04:28 PM

Title: Determination of the final temperature inside a calorimeter
Post by: soaring206 on December 08, 2004, 08:04:28 PM
Okay, I'm working on some pchem problems and I'm stuck on this one question...

A 5.33g piece of Cu metal is heated to 372.85K in boiling water, then dropped into a calorimeter containing 99.53g of water at 295.75K.  The calorimeter is sealed to the outside environment, and the temperature equalizes.  Cp[Cu(s)]=0.385 J/g*K, Cp[water]=4.184 J/g*K.  What is the final temperature inside the system?  What is the entropy change of the Cu metal?  What is the entropy change of the liquid water?  What is the total entropy change in the system?

I have absolutely no idea how to find the final temp of the system.  Once I have that temp, I think I can figure out the entropy changes, but if someone could point me in the right direction for finding the final temperature, that would be great.  Thank you in advance!
Title: Re:Determination of the final temperature inside a calorimeter
Post by: Demotivator on December 08, 2004, 10:04:16 PM
q = qobj + qcal + qw = 0  q is heat, net change is zero since the all the heat is contained in the system.

qobj = mobj x Cobj ( Tf - Tobj )  where qobj will be negative, because the hot object will lose heat to the calorimeter and water.

qcal = Ccal ( Tf - Ti )    If  there is no value given for Ccal,  ignore it.
qw = mw x Cw ( Tf - Ti )
Title: Re:Determination of the final temperature inside a calorimeter
Post by: soaring206 on December 08, 2004, 10:17:08 PM
Thank you so much!