Thermodynamics and Thermochemistry - Result Question 58

73. An athlete is given $100$ g of glucose $\left(\mathrm{C}6 \mathrm{H}{12} \mathrm{O}_6\right)$ of energy equivalent to $1560$ kJ . He utilizes $50$ per cent of this gained energy in the event. In order to avoid storage of energy in the body, calculate the weight of water he would need to perspire. The enthalpy of evaporation of water is $44 \mathrm{~kJ} / \mathrm{mol}$.

(1989, 2M)

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Answer:

Correct Answer: 73. $(318.96$ $ g)$

Solution:

  1. Moles of $\mathrm{H}_2 \mathrm{O}$ needs to perspire $=\frac{1560}{2 \times 44}=17.72$

Weight of water needs to perspire $=17.72 \times 18=318.96 \mathrm{~g}$