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This is College Physics Answers
with Shaun Dychko.
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This person consumes 3000
kilocalories of food energy
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and half of that we are told is lost due
to the evaporation of water.
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So the amount of heat absorbed by
that water is its mass
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times the latent heat of vaporization at
37.0 degrees Celsius
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and we can solve this for *m*
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by dividing both sides by latent
heat of vaporization
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and we get that the mass then is
3000 *kcal* divided by 2 times
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580 kilocalories per kilogram and
this is 2.59 kilograms of water.