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Example 4.8: Moles of Reactant Required in a Reaction

Moles of Reactant Required in a Reaction

How many moles of \(\ce{I2}\) are required to react with 0.429 mol of Al according to the following equation (see Figure 9)?


Figure 9 Aluminum and iodine react to produce aluminum iodide. The heat of the reaction vaporizes some of the solid iodine as a purple vapor. (credit: modification of work by Mark Ott)

Solution

Referring to the balanced chemical equation, the stoichiometric factor relating the two substances of interest is


The chemical amount of iodine is derived by multiplying the provided chemical amount of aluminum by this factor:


\(n_{\mathrm{\ce{Al}}}\) \(= 0.429\ \mathrm{mol}\)


\(n_{\mathrm{\ce{I2}}}\) \(= \frac{3 }{ 2} \cdot n_{\mathrm{\ce{Al}}}\)

\(\ \ \ =\frac{3 }{ 2} \cdot 0.429\ \mathrm{mol}\)

\(\ \ \ =0.643\ \mathrm{mol}\)