Problem Solving Strategies

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Wolgwang

10:51

@JohnRennie Hi!

John Rennie

@Wolgwang Hi :-)

Wolgwang

How are you? :-)

John Rennie

I'm good thanks :-) How are you?

Wolgwang

@JohnRennie Fine. Are you free?

John Rennie

I'm just finishing off another question. I shouldn't be long.

Wolgwang

10:56

Ok I will put my question.

> A child running a temperature of 101°F is given an antipyrin (i.e. a medicine that
lowers fever) which causes an increase in the rate of evaporation of sweat from his
body. If the fever is brought down to 98 °F in 20 minutes, what is the average rate
of extra evaporation caused, by the drug. Assume the evaporation mechanism to
be the only way by which heat is lost. The mass of the child is 30 kg. The specific
heat of human body is approximately the same as that of water, and latent heat of
evaporation of water at that temperature is about 580 cal g–1

Now, Heat lost by child=Heat gained by the water

Do I have to include the energy used to raise the temperature of water from 101degree F to boiling point in "heat gained by the water" or is the energy simply being used to convert state?

John Rennie

No, because the water is not heated to boiling. The only energy required is the latent heat of vaporisation.

Wolgwang

Ohk

Thanks

John Rennie

11:12

:-)

5 hours later…