Frequently Asked Question

The balanced chemical equation for the reaction is:

2Al + Cr2O3 → Al2O3 + 2Cr

To calculate the percent yield, we first need to determine the theoretical yield of Cr. The theoretical yield is the amount of product that would be produced if the reaction went to completion, based on the stoichiometry of the balanced chemical equation.

From the balanced chemical equation, we see that 1 mole of Cr2O3 reacts with 2 moles of Al to produce 2 moles of Cr. Therefore, the mole ratio of Cr2O3 to Cr is 1:2.

To convert the given mass of Cr2O3 to moles, we divide by the molar mass of Cr2O3 (151.99 g/mol):

44.1 g Cr2O3 × (1 mol Cr2O3 / 151.99 g Cr2O3) = 0.290 mol Cr2O3

According to the mole ratio, 0.290 mol of Cr2O3 will react to produce 0.580 mol of Cr.

To convert the moles of Cr to grams, we multiply by the molar mass of Cr (52.00 g/mol):

0.580 mol Cr × (52.00 g Cr / 1 mol Cr) = 30.16 g Cr

Therefore, the theoretical yield of Cr is 30.16 g.

Now we can calculate the percent yield using the following formula:

% yield = (actual yield / theoretical yield) × 100%

In this case, the actual yield is given as 25.6 g and the theoretical yield is 30.16 g. Substituting these values into the formula, we get:

% yield = (25.6 g / 30.16 g) × 100% = 84.9%

Therefore, the percent yield for this reaction is 84.9%.