Question

Study the balanced equation.

3Mg + Fe2O3 → 3MgO + 2Fe

What is the theoretical yield for MgO when 0.52 mol of Mg and 0.28 mol of Fe2O3 react?

2.10 x 101 mol MgO
1.03 x 101 mol MgO
2.10 x 101 g MgO
3.39 x 101 g MgO

Answer 1

Anyone?

Answer 2

3Mg + Fe2O3 → 3MgO + 2Fe
The limiting reagent (LR) must be determined.
0.52 mols Mg x (3 mol MgO/3 mol Mg) = 0.52 mol MgO or
0.28 mols Fe2O3 x (3 mol MgO/1 mol Fe2O3) = 0.84 mols MgO so Mg is the LR and it will produce as a theoretical yield 0.52 mols MgO.
So neither a nor b are correct for mols. Try grams.
molar mass MgO is 40.3 so grams MgO produced at 100% yield wil be
40.3 x 0.52 = 21 rounded to 2 places so you pick answer c.