C. there would have been no change of state, and the
temperature of the mixture might be represented as a distribution of the
79 deg. C. through the whole mass of the 2 kilograms, and so would be
39-1/2 deg. C. We say, therefore, the latent heat of water is the heat which
is absorbed or rendered latent when a unit of weight, say 1 kilogram of
water as ice, melts and liquefies to a unit of water at zero, or it is
79 heat units. These 79 units of heat would raise 79 units of weight of
liquid water through 1 deg. C., or one unit of liquid water through 79 deg..
Let us now inquire what the latent heat of steam is. If we take 1
kilogram of water at 0 deg. C. and blow steam from boiling water at 100 deg. C.
into it until the water just boils, and then stop and weigh the
resulting water, we shall find it amounts to 1.187 kilograms, so that
0.187 kilogram of water which was in the gaseous steam form, and had
besides a sensible heat of 100 deg. C., has changed its state to that of
liquid water. This liquid water, being at the boiling-point, has still
the 100 deg.
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