Consider this reaction: Fe3O4(s)+4CO(g) --> 4CO2(g)+3Fe(s). If you begin with 0.03820 moles of iron oxide and 0.120 moles of carbon monoxide, how many grams of iron can be formed? Indicate which reactant is the limiting reactant.
0.03820 x 3/1= 0.1146 moles x 55.8 g
0.120 x 1/4= 0.03 moles x 55.8 g
9.8 g
You need 4 mols of CO for every 1 mol of Fe
4 * .03820 = .153
so we need .153 mols of CO
BUT
we only have .120 mols of CO so the CO limits or controls the reaction
so we actually use .120/4 = .0300 mols of Fe3O4
that means we have .0300 *3 mols of Fe = .0900 mols Fe on each side
so
.0900 * 55.8 grams/mol = 5.02 grams Fe
correction to first line Fe3O4 not Fe
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You need 4 mols of CO for every 1 mol of Fe3O4
4 * .03820 = .153
so we need .153 mols of CO
BUT
we only have .120 mols of CO so the CO limits or controls the reaction
so we actually use .120/4 = .0300 mols of Fe3O4
that means we have .0300 *3 mols of Fe = .0900 mols Fe on each side
so
.0900 * 55.8 grams/mol = 5.02 grams Fe
I agree with 5.02 g Fe produced.
To determine which reactant is the limiting reactant, we need to compare the moles of iron oxide (Fe3O4) and carbon monoxide (CO) based on the balanced chemical equation.
From the equation, we can see that the stoichiometric ratio between Fe3O4 and CO is 1:4, which means for every 1 mole of Fe3O4, we need 4 moles of CO.
Given that we have 0.03820 moles of Fe3O4 and 0.120 moles of CO, we can calculate the moles of Fe that can be formed from each reactant.
For Fe3O4:
0.03820 moles of Fe3O4 x 3 moles of Fe / 1 mole of Fe3O4 = 0.1146 moles of Fe
For CO:
0.120 moles of CO x 1 mole of Fe / 4 moles of CO = 0.03 moles of Fe
Based on the calculations, we can see that the limiting reactant is CO because it can only produce 0.03 moles of Fe, while Fe3O4 can produce 0.1146 moles of Fe.
To calculate the grams of iron formed, we can multiply the moles of Fe by its molar mass, which is 55.8 g/mol.
For CO:
0.03 moles of Fe x 55.8 g/mol = 1.674 g of Fe formed
Therefore, when 0.120 moles of CO react with 0.03820 moles of Fe3O4, only 1.674 grams of Fe can be formed.