In a reaction of iron and oxygen to produce iron (III) oxide, 2.1 g of iron were completely consumed. What are the percent yield and percent error if 2.5 g of iron (III) oxide is actually produced?

The air is going to come out because of the low pressure.

The molar mass of a substance is defined as the mass of 1 mol of that substance, expressed in grams per mole, and is equal to the mass of 6.022 × 10 23 atoms, molecules, or formula units of that substance.