Given the following equation: 8Fe+S8=8FeS

a. If 4.2 moles of sulfur react, what is the mass of FeS produced?

b. if 13 moles of Fe react, what is the mass of FeS produced?

a. 2954g of FeS

b. 1143g of FeS

Explanation:

Based on the reaction:

8 Fe + S₈ → 8 FeS

8 moles of Fe reacts with 1 mole of S₈ to produce 8 moles of FeS

a. 4.2mol sulfur produce:

4.2mol S₈ × ( 8 mol FeS / 1 mol S₈) = 33.6mol FeS. As molar mass of FeS is 87.92g/mol, mass is:

33.6mol FeS × ( 87.92g / 1 mol FeS) = 2954g of FeS

b. 13mol Fe produce:

13mol Fe × ( 8 mol FeS / 8 mol Fe) = 13mol FeS. In mass:

13 mol FeS × ( 87.92g / 1 mol FeS) = 1143g of FeS

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"