The reaction of Cr2O3 with silicon metal at high temperatures will make chromium metal.

2Cr2O3(s)+3Si(s) > 4Cr(l)+3SiO2(s)

The reaction is begun with 161.00 g of Si and 139.00 g of Cr2O3.

How many grams of the excess reactant is left after the reaction is complete?

122.9 g of will be left from the given masses of both reactants.

Explanation:

To calculate the moles :

According to stoichiometry :

2 moles of require 3 moles of

Thus 0.91 moles of will require= of

Thus is the limiting reagent as it limits the formation of product and is the excess reagent.

Thus (5.75-1.36) = 4.39 moles  of excess reagent.

Mass of

Thus 122.9 g of will be left from the given masses of both reactants.

i think 4.44 moles