Silicon carbide, SiC, is commonly known as carborundum. This hard substance, which is used commercially as an abrasive, is made by heating SiO2 and C to high temperatures. SiO2(s) + 3C(s) → SiC(s) + 2CO(g)
How many grams of SiC form when 3.00 g of SiO2 and 4.50 g of C are allowed to react?

Mass of SiC = 2 g

Given

Reaction

SiO₂(s) + 3C(s) → SiC(s) + 2CO(g)

3.00 g of SiO₂

4.50 g of C

Required

mass of SiC

Solution

mol SiO₂ (MW=60,08 g/mol) :

= 3 g : 60.08 g/mol

= 0.0499

mol C(Ar = 12 g/mol) :

= 4.5 g : 12 g/mol

= 0.375

mol : coefficient of reactants =

SiO₂ : 0.0499/1 = 0.0499

C : 0.375/3 = 0.125

SiO₂ as a limiting reactant(smaller ratio)

Mol SiC based on mol SiO₂ = 0.0499

Mass SiC :

= mol x MW

= 0.0499 x 40,11 g/mol

= 2 g