SiO2 + 3C = SiC + 2CO; If 100 g of SiO2 and 100 g of C are reacted as far as possible, which one of the following statements will be correct?

Question

(a) 111 g of SiO2 will be left over.

(b) 44 g of SiO2 will be left over.

(c) 82 g of C will be left over.

(d) 40 g of C will be left over.

(e) Both reactants will be consumed completely, with none of either left over

Answer 1

Check that the equation is balanced which it is.

100g SiO₂ / (28.09 + 2*16 g/mol) = 1.66 mol SiO₂

100 g C / 12.01 g/mol = 8.33 mol C

Based on the reaction above, SiO₂ and C react in a 1 mol: 3 mol ratio

1.66 mol SiO₂ will consume 4.98 mol of C --> all of SiO₂ is consumed, and 3.35 mol C is left over (8.33-4.98 mol)

3.35 mol C * 12.01 g/mol C = 40.23 g C left over --> D