Question

A person inhales $640 \,g$ of $O_{2}$ per day. If all $O_{2}$ is used for converting sugar into $CO _{2}$ and $H _{2} O$, how much sucrose $\left(C_{12} H_{22} O_{11}\right)$ is consumed in the body in one day and what is the heat evolved? $\Delta H$ for combustion of sucrose $=-5645 \, kJ \,mol ^{-1}$

• A. 530 g, 9403.34 kJ
• B. 570 g, 9408.34 kJ
• C. 500 g, 9402.27 kJ
• D. 520 g, 9435.21 kJ

Answer 1

Answer: (B)

$C_{12} H _{22} O _{11}+12 O _{2} \rightarrow 12 CO _{2}+11 H _{2} O$
$12 \times 12+1 \times 2212 \times 16 \times 2 \Delta_{C} H =-5645\, kJ$
$mol ^{-1}+11 \times 16=342=384$
$\because 384\, g$ of $O _{2}$ converts $=342 \,g$ of sugar
$\therefore 640\, g$ of $O _{2}$ will convert $=\frac{342 \times 640}{384}=570\, g$ of sugar. Again,
$\because 342 \,g$ of sucrose evolves heat $=5645\, kJ$
$\therefore 570 \,g$ of sucrose will evolve heat
$=\frac{5645 \times 570}{342}=9408.33 \,kJ$