1. Ice of mass 0.5 kg at 0 degree C is mixed with 1 kg of water at 20 degree C.
Assume that there is no energy transfer between the "mixture" and the surroundings. Find the final temperature of the "mixture".
Can anyone help me???
Thanks a lot!!
F3Physics....Help!!!
2011-04-27 12:19 am
回答 (2)
2011-04-27 1:05 am
✔ 最佳答案
Heat given out by 1 kg water when cooled from 20'C to 0'C= 1 x 4200 x 20 J = 84 000 J
Heat required to melt all 0.5 kg of ice
= 0.5 x 330000 J = 165 000 J
It is thus clear that the heat released by the 1 kg water is not sufficient to melt all the 0.5 kg ice.
Hence, only part of the 0.5 kg of ice is melted. The final mixture thus consists of ice and water in equilibrium and is at 0'C, the melting point of ice.
2011-04-27 12:32 am
Let T be the final tempreature of the mixture.
(0.5)(334000) + (0.5)(4200)(T-0) = (1)(4200)(20-T)
167000 + 2100T = 84000 - 4200T
83000 = -6300T
T = -13 degree
So the final temperature is 0 degree.
If your answer is neagative , that means the mixture consist both ice and water. They have the same temperature ( 0 degree ).
Hope I can help you ~
(0.5)(334000) + (0.5)(4200)(T-0) = (1)(4200)(20-T)
167000 + 2100T = 84000 - 4200T
83000 = -6300T
T = -13 degree
So the final temperature is 0 degree.
If your answer is neagative , that means the mixture consist both ice and water. They have the same temperature ( 0 degree ).
Hope I can help you ~
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