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dalcde
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Two questions:
1.1. Homework Statement
Steam at 100 °C is pumped into an insulating pot containing a mixture of ice and water at 0°C. There are 0.4kg of ice and 1.6kg of water in the pot. Assume there is no heat lost to the surroundings, how much steam (in kg) is needed so that all ice is just melt?
specific heat capacity of water = 4200 Jkg-1°C-1
specific latent heat of fusion/vaporization = 334000/2260000 Jkg-1
1.2. Homework Equations
E = mcΔT
E = ml
1.3. The Attempt at a Solution
Energy released by steam going to 0°C (per kg of steam)
=(2260000 + 4200*100) J kg-1
=2680000 J kg-1
Energy needed to turn 0.4kg of ice into water
=0.4*334000 J
=133600 J
Amount of steam needed
=133600/2680000 kg
=0.0499kg
However, the answer is 0.591kg. What have I done wrong?2.1. Homework Statement
4kg of ice at -10°C is mixed with 0.1kg of water at 10°C. What is the final state of the mixture? What is the final temperature of the mixture?
specific heat capacity of ice = 2100 Jkg-1°C-12.2. Homework Equations
Same as above2.3. The Attempt at a Solution
Energy required to freeze the water
=0.1*10*4200+334000*0.1 J
=37600 J
[tex]4(T+10)\times 2100 = 0.1(-T)\times 2100 + 37600[/tex]
[tex]T=-5.39[/tex]
So final state is solid and final temperature is -5.39°C. Answer says that final temperature is 0°C. What have I done wrong?
1.1. Homework Statement
Steam at 100 °C is pumped into an insulating pot containing a mixture of ice and water at 0°C. There are 0.4kg of ice and 1.6kg of water in the pot. Assume there is no heat lost to the surroundings, how much steam (in kg) is needed so that all ice is just melt?
specific heat capacity of water = 4200 Jkg-1°C-1
specific latent heat of fusion/vaporization = 334000/2260000 Jkg-1
1.2. Homework Equations
E = mcΔT
E = ml
1.3. The Attempt at a Solution
Energy released by steam going to 0°C (per kg of steam)
=(2260000 + 4200*100) J kg-1
=2680000 J kg-1
Energy needed to turn 0.4kg of ice into water
=0.4*334000 J
=133600 J
Amount of steam needed
=133600/2680000 kg
=0.0499kg
However, the answer is 0.591kg. What have I done wrong?2.1. Homework Statement
4kg of ice at -10°C is mixed with 0.1kg of water at 10°C. What is the final state of the mixture? What is the final temperature of the mixture?
specific heat capacity of ice = 2100 Jkg-1°C-12.2. Homework Equations
Same as above2.3. The Attempt at a Solution
Energy required to freeze the water
=0.1*10*4200+334000*0.1 J
=37600 J
[tex]4(T+10)\times 2100 = 0.1(-T)\times 2100 + 37600[/tex]
[tex]T=-5.39[/tex]
So final state is solid and final temperature is -5.39°C. Answer says that final temperature is 0°C. What have I done wrong?
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