Question

If 150 kJ of energy is needed for muscular work to walk a distance of one km, then how much of glucose one has to consume to walk a distance of provided only 30% energy is available for muscular work. The enthalpy of combustionof glucose is 3000 $kJ mol^{-1}$'

• A. 75 g
• B. 30 g
• C. 180 g
• D. 150 g

Answer 1

Answer: (D)

150 g

Answer 2

Energy consumed for walking a distance of 5 km = 150 $\times$ 5 kJ = 750 kJ 1 mole of glucose, $C_6H_{12}O_6$ (180 g) gives theoretically energy = 3000 kJ Actual energy available = $\frac{30}{100} \times$ 3000 = 900 kJ Thus for 900 kJ of energy, glucose required = 180 g $\therefore$ for 750 kJ of energy, glucose required = $\frac{180}{900} \times 750$ = 150 g