Question

Assume the weight of an average adult is 70. kg, and that 420. kJ of heat are evolved per mole of oxygen consumed as a result of the oxidation of foodstuffs, knowing that the number of moles of O2 inhaled per minutes are 0.02 mol/min. Suppose an adult body were encased in a thermally insulating barrier. If as a result of this barrier all the heat evolved by metabolism of foodstuffs were retained by the body, what would the temperature difference of the body reach after 3 hours

Answer 1

Answer:

The temperature difference of the body after 3 hours = 5.16 K

Explanation:

we know that the number of moles of O₂ inhaled are 0.02 mole/min⁻¹

                                   or, 1.2 mole.h⁻¹

The average heat evolved by the oxidation of foodstuffs is then:

⇒          Q avg =$\frac{1.2 X 420 X 10^{3} }{70}$ = 7.2 kj.h⁻¹.Kg⁻¹

the heat produced after 3 h would be:

                 =    7.2 kj. h⁻¹.Kg⁻¹ x 3 h

                 = 21.6 kj. kg⁻¹

                 = 21.6 x 10³ j kg⁻¹

We know Qp = Cp x ΔT

Assume the heat capacity of the body is 4.18 J g⁻¹K⁻¹

⇒ ΔT = $\frac{Qp}{Cp}$

⇒ ΔT = $\frac{(21.6 X 10^{3} j.kg^{-1} ) }{(4.18 j k^{-1}g^{-1}) X (1000g.kg^{-1} )}$

⇒ ΔT = 5.16 K