Middle School

Determine the limiting reactant when a mixture of [tex]5.00 \times 10^3 \text{ g}[/tex] SiO2 and [tex]5.00 \times 10^3 \text{ g}[/tex] carbon react. What is the theoretical yield of silicon carbide?

Answer :

Final answer:

The limiting reactant in the reaction between SiO2 and carbon is SiO2. The theoretical yield of silicon carbide is 83.17 mol.

Explanation:

In order to determine the limiting reactant, we need to compare the amounts of each reactant and find the one that will be completely consumed first. We can calculate the number of moles of each reactant by dividing the given mass by the molar mass. The balanced equation for the reaction between SiO2 and carbon is:

SiO2 + 3C → SiC + 2CO

The molar mass of SiO2 is 60.08 g/mol and the molar mass of carbon is 12.01 g/mol. Using these values, we find that there are 5.00 × 103 g SiO2 and 5.00 × 103 g of carbon present. Converting these masses to moles, we get:

SiO2: (5.00 × 103 g) / (60.08 g/mol) ≈ 83.17 mol

Carbon: (5.00 × 103 g) / (12.01 g/mol) ≈ 416.32 mol

Since the stoichiometry of the reaction is 1:3 for SiO2 to carbon, we can see that there is an excess of carbon and SiO2 is the limiting reactant. Now, to find the theoretical yield of silicon carbide, we can use the mole ratio between SiO2 and SiC, which is 1:1. Using the moles of SiO2 we calculated earlier, we can say that the theoretical yield of SiC is 83.17 mol.