Question

#17 given the following reaction and the amounts of reactants determine the mass in grams of hydrogen that can be produced

Answer 1

First, we have the amounts of each reactant involved in the chemical reaction (we have to check if it is balanced). Then, we have to calculate the amount of hydrogen that can be produced.

The reaction is balanced because there are on each side: 2 atoms of aluminum, 6 atoms of hydrogen, and 6 atoms of chloride.

Then, we have to find out which one is the limiting reactant. We are going to use the next division to determine it:

`\alpha=\frac{moles\text{ reactant}}{respective\text{ }stoichiometric\text{ coefficient}}`

The reactant with the lowest α value will be the limiting reactant:

`\begin{gathered} Al:\text{ }\alpha=\frac{5.33\text{ mol}}{2}=\text{ 2.665} \\ \\ HCl:\text{ }\alpha=\frac{1.28\text{ mol}}{6}=\text{ 0.213} \end{gathered}`

Then, it means that the limiting reactant is the HCl. So, we calculate the amount of produced hydrogen, based on this compound quantity:

`1.28\text{ mol HCl * }\frac{3\text{ mol H}_2}{6\text{ mol HCl}}=\text{ 0.64 mol H}_2`

After this, we have to calculate the molecular weight of the hydrogen:

`M.W.\text{ H}_2=\text{ 1.007*2= 2.014 g/mol}`

And we finally, convert the moles to grams using the molecular weight that we have just calculated:

`0.64\text{ mol H}_2*\frac{2.014\text{ g}}{1\text{ mol}}=1.29\text{ g H}_2`

Then, the answer is that the produced mass of hydrogen is 1.29 g approx.