C (s) + S8 (s) → CS2 (l)

How many grams of carbon disulfide will be produced if 7.70 g of C and 19.7 g of S8 are allowed to react completely?

The balanced chemical reaction is written as:

4C (s) + S8 (s) → 4CS2 (l)

We are given the amount of carbon and sulfur to be used in the reaction. We need to determine first the limiting reactant to be able to solve this correctly.

7.70 g C (1 mol / 12.01 g) = 0.64 mol C

19.7 g S8 (1 mol / 256.48 g) = 0.08 mol S8

The limiting reactant would be S8. We use this amount to calculate.

0.08 mol S8 (4 mol CS2 / 1 mol S8) (256.48 g / 1 mol) = 78.8 g CS2