Chapter 9, Problem 2STP

Interpretation Introduction

Interpretation: The number of moles of ${\text{O}}_2(g)$ required to react completely with 2.0 moles of sugar needs to be calculated.

Concept introduction:The ratio of mass of substance to its molar mass is said to be number of moles of that substance.

The ratio of amount of any two compounds involved in a chemical reaction in terms of mole is said to be mole ratio, and used as a conversion factor between reactants and products.

Answer to Problem 2STP

The correct answer is option (b): $\text{24}$ .

Explanation of Solution

Given:

The balanced chemical reaction:

  ${\text{C}}_{12}{\text{H}}_{\text{22}}{\text{O}}_{11}(s)+{\text{ 12O}}_2(g)\to {\text{ 12CO}}_2(g){\text{ + 11H}}_2\text{O}(g)$

From the balanced chemical reaction, the mole ratio of sugar and oxygen is 1:12 so, the number of moles of oxygen required for 2.0 moles of sugar is:

  $\text{2}{\text{.0 mol of C}}_{12}{\text{H}}_{\text{22}}{\text{O}}_{11}\text{×}\frac{{\text{12 mol of O}}_{\text{2}}}{{\text{1 mol of C}}_{12}{\text{H}}_{\text{22}}{\text{O}}_{11}}{\text{ = 24 mol of O}}_{\text{2}}$

Hence, the number of moles of ${\text{O}}_2(g)$ required to react completely with 2.0 moles of sugar is $\text{24}$ .