Required Volume of a Gaseous Reactant

The ratio of combination of CO and O2 is 2 1, whether we are talking about moles or units of volume. Thus, if we want to determine the stoichiometric amount [ W Section 3.6] of O2 required to combine with a particular volume of CO, we simply use the conversion factor provided by the balanced equation, which can be expressed as any of the following  

Let s say we want to determine what volume of O2 is required to react completely with 65.8 mL of CO at STP. We could use the ideal gas equation to convert the volume of CO to moles, use the stoichiometric conversion factor to convert to moles O2, and then use the ideal gas equation again to convert moles O2 to volume. But this method involves several unnecessary steps. We get the same result simply by using the conversion factor expressed in miUihters  

In cases where only one of the reactants is a gas, we do need to use the ideal gas equation in our analysis. Recall, for example, the reaction of sodium metal and chlorine gas used to illustrate the Bom-Haber cycle Section 8.2]  

Given moles (or more commonly the mass) of Na, and information regarding temperature and pressure, we can determine the volume of CI2 required to react completely  

Sample Problem 11.8 shows how to use the ideal gas equation in a stoichiometric arralysis. 

---