Finding Grams of Complete Reaction

Question

I found the balanced equation : 4C + S8 = 4CS2, but I am confused about how to find the grams.

Any help is greatly appreciated!

Consider the following unbalanced reaction: 

C_(s) + S_8(s) → CS_2(l) 

How many grams of carbon disulfide will be produced if 6.70 g of C and 15.5 g of S₈ are allowed to react completely? 

Report your answer to 3 significant figures and do not include units. 

To enter a number in scientific notation, such as 1.5x10^-4, use the following notation: 1.5E-4.

Answer 1

First, you must balance the equation:

4C_(s) + S_8(s) → 4CS_2(l) 

Next, since there are two reactants, one must determine which, if any, is LIMITING:

6.7 g C x 1 mol C/12.0 g x 4 mol CS₂/4 mol C x 76.14 g/mol CS₂ = 38.7 g CS₂ can be formed

15.5 g S₈ x 1 mol S₈/256.5 g x 4 mol CS₂/mol S₈ x 76.14 g/mol CS₂ = 18.4 g CS₂ can be formed

Thus, S₈ is limiting.

ANSWER = 1.84E¹ if scientific notation is desired, or 18.4 if not.