Question

Carborundum is silicon carbide, SiC, a very hard material used as an abrasive on sandpaper and in other applications. It is prepared by the reaction of pure sand, SiO₂, with carbon at high temperature. Carbon monoxide, CO, is the other product of this reaction. Write the balanced equation for the reaction, and calculate how much SiO₂ is required to produce 3.00 kg of SiC.

a) 2SiO₂ + 3C ⟶ 2SiC + 2CO; 4.55 kg
b) 3SiO₂ + 4C ⟶ 3SiC + 2CO; 4.00 kg
c) SiO₂ + 2C ⟶ SiC + CO; 3.00 kg
d) 2SiO₂ + 5C ⟶ 2SiC + 3CO; 3.50 kg

Answer 1

The balanced chemical equation for producing silicon carbide from sand and carbon is SiO₂ + 3C → SiC + 2CO. To produce 3.00 kg of SiC, approximately 4.50 kg of SiO₂ is required, which matches option (c).

Step-by-step explanation:

The reaction of pure sand (SiO₂) with carbon to produce silicon carbide (SiC) and carbon monoxide (CO) is represented by a balanced chemical equation. The correct equation for this reaction is SiO₂ + 3C → SiC + 2CO.

To calculate how much SiO₂ is required to produce 3.00 kg of SiC, we can use stoichiometry. The molar mass of SiC is 40.10 grams per mole (Si = 28.09, C = 12.01), and the molar mass of SiO₂ is 60.09 grams per mole (Si = 28.09, O = 2 x 16). Using these masses, we can set up a proportion based on the stoichiometry of the balanced equation:

1 mole of SiC is produced by 1 mole of SiO₂. 3000 grams SiC × (1 mole SiC/40.10 grams SiC) × (60.09 grams SiO₂/1 mole SiO₂) = 4501.35 grams of SiO₂, which is approximately 4.50 kg of SiO₂ required. Thus, the correct answer is option (c): SiO₂ + 2C → SiC + CO; 3.00 kg.