Question

A person inhales $640g$ of $O_2$ per day. If all $O_2$ is used for converting sugar into $C{O}_2$ 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 $=-5645kJmo{l}^{-1}$

• 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)

$C_{12}{H}_{22}{O}_{11}+12O_2\to 12C{O}_2+11H_{2}O$
$12\times 12+1\times 2212\times 16\times 2{\Delta }_{C}H=-5645kJ$
$mo{l}^{-1}+11\times 16=342=384$
$\because 384g$ of $O_2$ converts $=342g$ of sugar
$\therefore 640g$ of $O_2$ will convert $=\frac{342\times 640}{384}=570g$ of sugar. Again,
$\because 342g$ of sucrose evolves heat $=5645kJ$
$\therefore 570g$ of sucrose will evolve heat
$=\frac{5645\times 570}{342}=9408.33kJ$