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q = (m)(Dt)(cp)
where q is the energy in joules
m is the mass
Dt is the change in initial temperature to the final
temperature
cp is the specific heat (heat required to raise 1 g of the substance 1C)
1) q = (m)(Dt)(cp)
2.5 x 103 J = (1.0 x 104
g)(70C-10C)(cp)
[2.5 x 103
J]
= cp
[1.0 x 104 g][70C-10C]
0.0042 J = cp
gC
--------------------------------------------------------------------------------------------------------------
2) qmetal = (m)(Dt)(cp)
qwater = (m)(Dt)(cp)
qmetal = qwater
(m)(Dt)(cp)
= (m)(Dt)(cp)
[1.0Kg][100C-Tf][0.50KJ]
= [50.0g][Tf-20C][4.184 J]
[ KgC]
[ gC ]
[1.0Kg][1000g][100C-Tf][0.50KJ][
1Kg][1000J] = [50.0g][Tf-20C][4.184 J]
[
1Kg]
[ KgC][1000g][
1KJ]
[ gC ]
[1000g][100C-Tf][0.50J]
= [50.0g][Tf-20C][4.184 J]
[ gC]
[ gC ]
[1000g][100C-Tf][0.50
J/gC] = [Tf-20C]
[
50.0g]
[4.184 J/gC]
[2.39][100C-Tf] =
[Tf-20C]
239C-2.39Tf
= Tf-20C
239C + 20C = Tf
+ 2.39Tf
259C =
3.39Tf
259C = Tf
3.39
76C
= Tf
---------------------------------------------------------------------------------------------------------------
3)
qmetal = (m)(Dt)(cp)
qwater = (m)(Dt)(cp)
qmetal = qwater
(m)(Dt)(cp)
= (m)(Dt)(cp)
[2.80Kg][100C-Tf][0.43KJ]
= [50.0g][Tf-30C][4.184 J]
[ KgC]
[ gC ]
[2.8.0Kg][1000g][100C-Tf][0.43KJ][
1Kg][1000J] = [50.0g][Tf-30C][4.184 J]
[
1Kg]
[ KgC][1000g][
1KJ]
[ gC ]
[2800g][100C-Tf][0.43J]
= [50.0g][Tf-30C][4.184 J]
[ gC]
[ gC ]
[2800g][100C-Tf][0.43
J/gC] = [Tf-30C]
[
50.0g]
[4.184 J/gC]
[24.08][100C-Tf]
= [Tf-30C]
2408C-24.08Tf
= Tf-30C
2408C + 30C = Tf
+ 24.08Tf
2438C
= 25.08Tf
2438C = Tf
325.08
97C
= Tf
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