A sheet of gold weighing 10.0 g and at a temperature of 18.0C is placed flat on a sheet of iron weighing 20.0 g and at a temperature of 55.6 C.
What is the final temperature of the combined metals?
Assume that no heat is lost to the surroundings.
[ Hint: The heat gained by the gold must be equal to the heat lost by the iron. The specific heats of the metals are: Au(s) = 0.129 J/g-C; Fe(s) = 0.444 J/g-C ]
The ANSWER is 50.7 C.
However, I need to know how to work it out.... so please help. and thank u.
Calorimetry: What is the final temperature?
2009-02-27 2:41 pm
回答 (2)
2009-02-27 3:17 pm
✔ 最佳答案
Let the final temperature be T°C.For the gold: Heat gained = mass * spec heat * change in temp
Au = 10*(T-18) * 0.129
For the iron, Heat lost = mass * spec heat * change in temp.
Fe = 20 * (55.6-T) * 0.444
Heat gain = heat lost
1.29(T-18) = 8.88*( 55.6-T)
1.29T - 23.22 = 493.73 - 8.88T
10.17 T = 516.95
T = 516.95/10.17
T = 50.8°C
Final temperature = 50.8°C
2009-02-27 3:10 pm
i) first it we understand heat must flow from the iron to gold since iron is at a higher temperature than gold and we should note that temperature is the property that determine heat flow in a system
Data
mass of gold,m'=10.0g mass of iron m=20.0g( this mass in g should be converted to kg)
initial temperature of iron, @' =55.6C That of gold @''=18.0C.
This system when in thermal contact they well reach a thermal equilibrium of state when there will be no net heat flow and will have a common property as final temperature,@
from i)
(heat supplied by iron to have a temperature change from @' to @) =(heat gain by gold to have temperature change from @' to @)
physics ends here
m'c'(@-@' )=mC(@-@'' ).............I)
SOLVE THIS MAHTS AND MAKE THE REQUIRE TEMPERATURE THE SUBJECT(@)
Data
mass of gold,m'=10.0g mass of iron m=20.0g( this mass in g should be converted to kg)
initial temperature of iron, @' =55.6C That of gold @''=18.0C.
This system when in thermal contact they well reach a thermal equilibrium of state when there will be no net heat flow and will have a common property as final temperature,@
from i)
(heat supplied by iron to have a temperature change from @' to @) =(heat gain by gold to have temperature change from @' to @)
physics ends here
m'c'(@-@' )=mC(@-@'' ).............I)
SOLVE THIS MAHTS AND MAKE THE REQUIRE TEMPERATURE THE SUBJECT(@)
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