JEE Main · 2023 · 25 Jan 2023 · Shift 1 · Chemical Thermodynamics

An athlete is given 100 g of glucose

(C_{6} H_{12} O_{6})

for energy. This is equivalent to 1800 kJ of energy. The

50%

of this energy gained is utilized by the athlete for sports activities at the event. In order to avoid storage of energy, the weight of extra water he would need to perspire is ______ g (Nearest integer)

Assume that there is no other way of consuming stored energy.

Given : The enthalpy of evaporation of water is 45

kJ mol^{- 1}

Molar mass of

C, H & O

are 12.1 and

16 g mol^{- 1}

Answer: 360

Solution

The glucose supplies

1800

kJ, of which half,

900

kJ, must be shed to prevent storage, and this heat leaves by evaporating perspiration. Since evaporating one mole of water absorbs

45

kJ, the water evaporated is

900/45 = 20

mol. Multiplying by the molar mass of water,

20 \times 18 = 360

. The athlete must perspire

360

g of water.

JEE Main · 2023 · 25 Jan 2023 · Shift 1 · Integer answer

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JEE Main · 2023 · 25 Jan 2023 · Shift 1 · Chemical Thermodynamics

Solution

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