Chromium(III) oxide (Cr2O3) reacts with silicon (Si) as indicated by the balanced equation below:
2Cr2O3(s) + 3Si(s) — 4Cr(s) + 3SiO2(s)
Determine the mass of SiO2 (60.08 g mol-4) when 30.00 g of Si reacts with 100.0 g of Cr2O3 (152 0 g mol-1).

Considering the definition of reaction stoichiometry and limiting reagent, the mass of SiO₂ that could be formed is 59.02 grams.

The balanced reaction is:

2 Cr₂O₃ + 3 Si → 4 Cr + 3 SiO₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, it is possible to use a simple rule of three as follows: if by stoichiometry 84 grams of Si reacts with 304 grams of Cr₂O₃, 30 grams of Si reacts with how much mass of Cr₂O₃?

mass of Cr₂O₃= 108.57 grams

But 108.57 grams of Cr₂O₃ are not available, 100 grams are available. Since you have less mass than you need to react with 30 grams of Si, Cr₂O₃ will be the limiting reagent.

Then, it is possible to determine the mass of SiO₂ produced by another rule of three, using the limiting reagent: if by stoichiometry 304 grams of Cr₂O₃ produce 180 grams of SiO₂, 100 grams of Cr₂O₃ how much mass of SiO₂ will be formed?

mass of SiO₂= 59.02 grams

In summary, the mass of SiO₂ that could be formed is 59.02 grams.

Learn more with this examples:

mass of SiO₂ = 59.70 g

Explanation:

2Cr₂O₃(s) + 3Si(s) — 4Cr(s) + 3SiO₂(s)

Let us determine the limiting reactant because it determines the amount of  product. The limiting reactant is totally consumed when the chemical reaction is completed.

Cr2O3

mass of Cr₂O₃ = 100 g

molar mass of Cr₂O₃ = 152 g/mol

moles = 100/152

moles = 0.6578947368 moles

moles = 0.658 moles

from the reaction

2 moles of Cr₂O₃ produces 3 moles of SiO₂

0.658 moles will give  (3 × 0.658)/2 = 1.974/2 = 0.987 moles

Si

mass of Si = 30 g

molar mass of Si = 28 g/mol

moles =  30/28

moles = 1.07142 moles

3 moles of Si gives  3 moles of SiO₂

1.07142 moles of Si will give 1.07142 moles of  SiO₂

The limiting reactant is Cr₂O₃ since it produce the smallest quantity of product .

The mass of SiO₂ can now be calculated as follows :

molar mass of SiO₂ = 60.08

2(152) g of Cr₂O₃ produces 3 (60.08) g of SiO₂

100 g of  Cr₂O₃ will produce ?

cross multiply

mass of SiO₂ =  (180.24 × 100 )/304

mass of SiO₂ = 18024/304

mass of SiO₂ = 59.289473684

mass of SiO₂ = 59.70 g

give me abc and i will get it for u.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)