An athlete is given 100 g of glucose () 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
Molar mass of C, H & O are 12, 1 and 16 g mol.
Assume that there is no other way of consuming stored energy.
Given : The enthalpy of evaporation of water is 45 kJ mol
Molar mass of C, H & O are 12, 1 and 16 g mol.
Show answer and solution
Answer: 360
Solution
The athlete uses 50% of 1800 kJ = 900 kJ for sports. The remaining 50% = 900 kJ must be dissipated via perspiration to avoid energy storage.
Moles of water needed to evaporate = 900 kJ ÷ 45 kJ/mol = 20 mol.
Mass of water = 20 × 18 g/mol = 360 g.
Moles of water needed to evaporate = 900 kJ ÷ 45 kJ/mol = 20 mol.
Mass of water = 20 × 18 g/mol = 360 g.
[JEE Main 2023 · 25 Jan · Shift 1]