Reaction Stoichiometry How Much Carbon Dioxide

The balanced chemical equations for fossil-fuel combustion reactions provide the exact relationships between the amount of fossil fuel burned and the amount of carbon dioxide emitted. In this discussion, we use octane (a component of gasoline) as a representative fossil fuel. The balanced equation for the combustion of octane is  

A FIGURE 4.3 Global Temperature Average temperatures worldwide have risen by about 0.7 °C since 1880. 

The balanced equation shows that 16 CO2 molecules are produced for every 2 molecules of octane burned. We can extend this numerical relationship between molecules to the amounts in moles as follows  

The coefficients in a chemical equation specify the relative amounts in 

In other words, from the equation, we know that 16 moles of CO2 are produced for every 2 moles of octane burned. The numerical relationships between chemical amounts in a balanced chemical equation are called reaction stoichiometry. Stoichiometry allows us to predict the amounts of products that will form in a chemical reaction based on the amounts of reactants that react. Stoichiometry also allows us to determine the amount of reactants necessary to form a given amount of product. These calculations are central to chemistry, allowing chemists to plan and carry out chemical reactions to obtain products in the desired quantities. 

---