To determine how much sulfur has been used in the chemical reaction, we can use the principle of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction.
According to the information given:
- Mass of iron = 60 grams
- Mass of iron sulfide produced = 90 grams
The mass of sulfur used can be calculated using the formula:
\[ \text{Mass of sulfur} = \text{Mass of iron sulfide} - \text{Mass of iron} \]
Substituting in the values:
\[ \text{Mass of sulfur} = 90 , \text{grams} - 60 , \text{grams} = 30 , \text{grams} \]
So the amount of sulfur used in the chemical reaction is 30 grams.
The correct answer is: A. 30 grams