1, shrimp dumplings are cooked by condensing steam on them. One such cooker supplies steam at 110度 at the rate of 0.1kg min^-1 . ( given c(steam)= 2000J kg^-1度^-1)
a) calulate the power,in watts,at which the steam cooker supplies energy if the steam condenses to water at 100度.
2.
0.1kg of melting ice is added to 0.5kg of water at30度 in a foam cup.find the final temperature of the mixture.
列埋步驟..thx=]
phy (heat)問題..
2007-10-29 1:56 am
回答 (2)
2007-10-29 2:26 am
✔ 最佳答案
1)E= (0.1)(2.27X10^6) +(0.1)(2000)(10)
=227000+2000
=229000
2)
let the final temperature be T
mc(三角形)t=mc(三角形)t
(0.1)(4200)(T-0)=(0.5)(4200)(30-T)
420T =63000-2100T
2520T =63000
T =14.3
the final temperature is 14.3度
參考: 自己
2007-10-29 3:26 am
1. Heat Q given out by the 110 deg. steam in condensing to water in 1 minute
Q = (0.1 x 2000 x 10 + 0.1 x L) J
where L is the specific latent heat of vapourization of water
Hence, power supplied by the steam = Q/60 Watts.
2. Let T be the final temperature of mixture
heat absorbed by ice = 0.1 x 334000 + 0.1 x 4200T
where 334000 is the specific latent heat of fusion of water
heat given out by water = 0.5 x 4200 x (30-T) J
equating the two ,
0.1 x 334000 + 0.1 x 4200T = 0.5 x 4200 x (30-T)
solve for T gives T=11.7 deg.C
Q = (0.1 x 2000 x 10 + 0.1 x L) J
where L is the specific latent heat of vapourization of water
Hence, power supplied by the steam = Q/60 Watts.
2. Let T be the final temperature of mixture
heat absorbed by ice = 0.1 x 334000 + 0.1 x 4200T
where 334000 is the specific latent heat of fusion of water
heat given out by water = 0.5 x 4200 x (30-T) J
equating the two ,
0.1 x 334000 + 0.1 x 4200T = 0.5 x 4200 x (30-T)
solve for T gives T=11.7 deg.C
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