1. A cube of ice is taken from the freezer at -5.5 C and placed in a 95-g alumin

Question

1.

A cube of ice is taken from the freezer at

-5.5 C and placed in a 95-g aluminum calorimeter filled with 330 g of water at room temperature of 20.0 C. The final situation is observed to be all water at 17.0 C. The specific heat of ice is 2100 J/kgC, the specific heat of aluminum is 900 J/kgC, the specific heat of water is is 4186 J/kgC, the heat of fusion of water is 333 kJ/Kg.

2.

One end of a 58-cm-long copper rod with a diameter of 1.8 cm is kept at 470 C, and the other is immersed in water at 20 C. Calculate the heat conduction rate along the rod.

3. A heat engine uses a heat source at 570 C and has an ideal (Carnot) efficiency of 28 % .To increase the ideal efficiency to 40 % , what must be the temperature of the heat source?

4.

What is the change in entropy of 260 g of steam at 100 C when it is condensed to water at 100 C?

Explanation / Answer

Let the mass of ice be m gram

intial temperature of ice = -5.5 deg C

heat to bring ice to 0 C = m*5.5*2.1 = 11.55m J

heat to melt the ice = mass * latent heat of fusion= m*333 = 333m J

heat to bring molten ice to 17 C = m * 17 * 4.186 = 71.162m J

So total heat required by ice to reach 17 C = (11.55+333+71.162)m = 415.712m J

heat given by aluminium = 95 * (20-17)*0.9 = 256.5 J

heat given by water = 330*(20-17)*4.186 = 4144.14 J

So total heat given = 256.5+4144.14 = 4400.64 J

Since  heat gained = heat lost

415.712m = 4400.64

=> m = 10.58579 g

So mass of ice = 10.58579 grams = 10.6 gram (aproximately)

[Note: Please post independent questions seperately]

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