Calculating Amounts of Reactant and Product

A balanced equation contains a wealth of quantitative information relating individual chemical entities, amounts of chemical entities, and masses of substances. It is essential for all calculations involving amounts of reactants and products if you know the number of moles of one substance, the balanced equation tells you the number of moles of all the others in the reaction. 

Stoichiometricolly Equivalent Molar Ratios from the Balanced Equation 

In a balanced equation, the number of moles of one substance is stoichiometri-cally equivalent to the number of moles of any other substance. The term stoi-chiometrically equivalent means that a definite amount of one substance is formed from, produces, or reacts with a definite amount of the other. These quantitative relationships are expressed as stoichiometricolly equivalent molar ratios that we use as conversion factors to calculate these amounts. Table 3.3 presents the quantitative information contained in the equation for the combustion of propane, a hydrocarbon fuel used in cooking and water heating  

If we view the reaction quantitatively in terms of CsHg, we see that 1 mol of C3H8 reacts with 5 mol of O2 1 mol of C3H8 produces 3 mol of CO2 1 mol of C3H8 produces 4 mol of H2O Therefore, in this reaction, 

We chose to look at C3H8, but any two of the substances are stoichiometrically equivalent to each other. Thus, 

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SAMPLE PROBLEM 3.1 0 Calculating Amounts of Reactant and Product... 

Calculating Amounts of Reactants and Products for a Reaction in Solution... 

Chemistry is mostly about reactions—processes in which groups of atoms are reorganized. So far we have learned to describe chemical reactions by using balanced equations and to calculate amounts of reactants and products. However, there are many important characteristics of reactions that we have not yet considered. 

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