Chapter 9, Problem 2A

Interpretation Introduction

Interpretation: The chemical equation for reaction between carbon and oxygen is given. The reason for no reaction of one gram of carbon with one gram of oxygen has to be explained.

Concept introduction: Stoichiometric coefficients determine the molar ratio between reactants and products. They do not determine the mass terms for reactants and products.

Answer to Problem 2A

The stoichiometric terms compare the molar ratio of reactants and products. These do not correspond to mass terms. The mass of carbon that reacts with one gram of oxygen is $2.67\text{g}$ .

Explanation of Solution

Given information : The mass of carbon is one gram and the mass of oxygen is one gram.

The given chemical equation for reaction between carbon and oxygen is shown below.

  $\text{C}+{\text{O}}_{\text{2}}\to {\text{CO}}_{\text{2}}$

The above equation shows that one mole of carbon undergoes reaction with one mole of oxygen and forms one mole of carbon dioxide as product. The mass of one mole of carbon is $12.0\text{g}$ and mass of one mole of oxygen is $32.0\text{g}$ . Thus, $12.0\text{g}$ of carbon undergoes reaction with $32.0\text{g}$ of oxygen. The amount of carbon that reacts with one gram of oxygen is shown below.

  $\begin{array}{c}\text{12}\text{g C}=\text{32}\text{g}{\text{O}}_{\text{2}}\\ \text{1}\text{g C}=\frac{\text{32}}{12}\text{g}{\text{O}}_{\text{2}}\\ =2.67\text{g}{\text{O}}_{\text{2}}\end{array}$

Thus, one gram of carbon cannot undergo reaction with one gram of oxygen.

Conclusion

The stoichiometric terms compare the molar ratio of reactants and products. These do not correspond to mass terms. The mass of carbon that reacts with one gram of oxygen is $2.67\text{g}$ .