a) The energy content of a Krispy Kreme donut is 1050 kJ. If a 70 kg person were

ID: 785814 • Letter: A

Question

a) The energy content of a Krispy Kreme donut is 1050 kJ. If a 70 kg person were a

closed thermodynamic system, calculate the body temperature rise that would result

from eating one donut. You may assume that the donut is completely metabolized and

that all of the heat evolved in the process is retained by the body. Also assume that the

heat capacity of the body is the same as that of liquid water, 4.18 J g?1 K?1.

b) Fortunately people are actually open systems and the main mechanism of heat loss

is the evaporation of water. How much water would the person above need to

evaporate after eating the donut to maintain a constant body temperature? The heat of

vaporization of water at 37 oC is 2402 J g?1.

a) 1050*1000=70*1000*4.18*rise in temperature .....rise in temperature = 3.59 degree b)1050*1000=m*2402 or m=437 g = 0.437 Kg

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.