Question
Chemistry Question on Thermodynamics
An athlete is given 100g of glucose (C6H12O6) for energy This is equivalent to 1800kJ 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 45kJmol−1 Molar mass of CH&O are 12,1 and 16gmol−1
Answer
The correct answer is 360.
C6H12O6(s)+6O2→6CO2(g)+6H2O(l)
Extra energy used to convert H2O(l) into H2O(l) into H2O(g)
=21800=900kJ
⇒900=nH2O×45
nH2O=45900=20 mole
WH2O=20×18=360g