Question

Aluminum reacts with excess copper(II) sulfate according to the unbalanced reaction

Answer 1

Answer: The mass of Cu produced is 4.88 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

Given mass of aluminum = 2.98 g

Molar mass of aluminum = 27 g/mol

Plugging values in equation 1:

$\text{Moles of aluminum}=\frac{2.98g}{27g/mol}=0.1104 mol$

The given chemical equation follows:

$2Al(s)+3CuSO_4(aq)\rightarrow Al_2(SO_4)_3(aq)+3Cu(s)$

By the stoichiometry of the reaction:

If 2 moles of aluminum produces 3 moles of Cu

So, 0.1104 moles aluminium will produce = $\frac{3}{2}\times 0.1104=0.1656mol$ of Cu

Molar mass of Cu = 63.5 g/mol

Plugging values in equation 1:

$\text{Mass of Cu}=(0.1656mol\times 63.5g/mol)=10.516g$

The percent yield of a reaction is calculated by using an equation:

$\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100$ ......(2)

Given values:

% yield of product = 46.4 %

Theoretical value of the product = 10.516 g

Plugging values in equation 2, we get:

$46.4=\frac{\text{Actual value of Cu}}{10.516g}\times 100\\\\\text{Actual value of Cu}=\frac{46.4\times 10.516}{100}\\\\\text{Actual value of Cu}=4.88g$

Hence, the mass of Cu produced is 4.88 g