Chemical Stoichiometry and Gases: Using Ideal Gas Law to Determine Moles

Recall that for a balanced chemical reaction, calculations involving the mass of the reactants and products and the number of moles are performed by following a general conceptual plan.

Here, the stoichiometric coefficients are used as conversion factors between the moles of the reactant and the moles of the product.

In chemical reactions involving gaseous substances, the amount of gas is typically specified in terms of its volume at a given temperature and pressure. This is because gases are fluid and expand to fill any available volume.

In gaseous reactions, the mole amount and volume of a gas are interrelated through the ideal gas law. In this way, the number of moles can be determined from the volume of the gas and vice versa.

Combining concepts of the ideal gas law, molar mass, and stoichiometry allows for calculations related to the volume, the number of moles, and the mass of gaseous reactants and products.

As an example, consider the reaction between lithium and water to produce hydrogen gas. Assuming that the reaction occurs at 291 K and 0.977 atm, what amount of lithium will produce 35.25 liters of hydrogen?

First, by applying the ideal gas law and substituting the given