How much water has been lost from a person exercising?

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During exercise, a person can lose water through evaporation, quantified by the heat given off, which is 180.0 kcal in this case. The latent heat of evaporation for water is 539 kcal/kg, leading to the formula Q = M x Lv to calculate the mass of water lost. By rearranging the formula to M = Q / Lv, the calculation yields approximately 0.334 kg of water lost. The discussion highlights confusion around rearranging formulas and applying given values correctly. Clarification on these points is essential for completing the assignment accurately.
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Homework Statement


During exercise a person may give off 180.0 kcal of heat in 30.0 minutes by evaporation of water from the skin. How much water has been lost? The latent heat of evaporation of water is 539 kcal/kg.


2. I believe the formula to use is Q=MxLv



3. I started with the above formula, but already got stuck on whether this formula needs to be re-arranged or not? Maybe Q=ML?
Q=(180.0kCal)(539kCal/kg)
= 0.334kg

I'm just not sure if this is complete or am i missing something? Any help would be great, this assignment is due 4pm today!
 
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I believe you have the right answer although I don't understand your method? You are solving for the mass, M not for heat, Q.
 
Oops, I meant to write: M=QL where,Q=180.0Kcal and L=539kCal/g?

I'm having trouble figuring out where to use given values in a formula and re-arranging formulas as we haven't gone over it in class yet..

Thanks for your help!
 
Last edited:
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