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In an insulated vessel, 250g of ice at 0 degC is added to 600g of water at 18 degC.

a) What is the final temperature of the system?
b) How much ice remains when the system reaches equilibrium?

For a, the correct answer is 0 degC, however I got a final temperature of 15.1 degC. I do not understand how 0 degC was achieved.

2007-01-27 19:01:53 · 1 answers · asked by Anonymous in Science & Mathematics Physics

1 answers

To melt all the ice, the water would have to supply 335*250 = 83,750 joule of energy to the ice. (Latent heat of fusion for ice = 335 joule/gm). The specific heat of water is 4.1 joule/gm ºK The energy for a temp change of ∆T of the water is 4.1*600*∆T = 83,750. From this, ∆T would need to be 34ºC. The water cannot drop below the temp of the ice, so the ice will not melt completely, and the equilibrium temperature will be the ice temperature, of 0ºC.

The actual energy lost by the water is the energy it took to melt the ice.

Energy lost by water = 18 * 4.1 * 600 = 44,280 joules; the mass of ice melted by that energy is 44,280/335 = 132.2 gm. You started with 250 gm of ice, so 117.8 gm remains.

2007-01-27 20:52:50 · answer #1 · answered by gp4rts 7 · 0 0

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