Cliffs AP Chemistry, 3rd Edition

(singke) #1

specific heat of aluminum = 0.902 J/g ⋅°C


specific heat of cola = 4.00 J/g ⋅°C


ti= 30 °C
tf= 10°C
(a) Restatement: Amount of heat absorbed by ice.
quantity of heat released by six pack = heat released by cans + cola
qsix-pack= qcans+ qcola
q= mass ×specific heat ×∆t

C

C

g

g

:

:

..


.

..


.
.

.,

q

q

q

1

6
1

50 0 0 902
1

10 30

5412 00

1

6
1

355
1

(^123400)
1
10 30
210 10
5412 2 10 10
2 15 10 215
cans
can
gAl J CC
J
cans
can
mL cola
mL cola
g cola J CC
J
JJ
Jor kJ
5
5
5
cans
cola
six pack







=






=-

=





=-
=- + -

=- -

%


%


%


%






%


%


`

`

_

j

j

i

Therefore, the amount of heat absorbed by the ice is 215 kJ.
(b) Restatement: Minimum amount of ice required to accomplish the necessary cooling.
For the systemto reach 10°C, the heat absorbed includesthe warming of the water.
Let x = mass of ice

././. CC

./

x g

x

(^215) 18 02^600 4 184 10
0 375
(^215573)
kJ kJ molemole J/g
kJ g
kJ g ice
=+:#



d nH ` %%j
Thermochemistry


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