Question

Combustion of glucose ($C_6H_{12}O_6$) produces $CO_2$ and water. The amount of oxygen (in g) required for the complete combustion of $900 \, \text{g}$ of glucose is:
$[ \text{Molar mass of glucose in g mol}^{-1} = 180 ]$

• A. 480
• B. 960
• C. 800
• D. 32

Answer 1

Answer: (B)

960

Answer 2

The balanced combustion reaction of glucose is:
$\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}.$
From the equation:
1 mol of glucose requires 6 mol of $\text{O}_2$.
Molar mass of glucose = $180 \, \text{g/mol}$.
Molar mass of $\text{O}_2 = 32 \, \text{g/mol}$.
Number of moles of glucose in $900 \, \text{g}$:
$n = \frac{900}{180} = 5 \, \text{mol}.$
Oxygen required:
$\text{Mass of } \text{O}_2 = 5 \cdot 6 \cdot 32 = 960 \, \text{g}.$
Final Answer:
$960 \, \text{g}$.