Step 1
The reaction provided:
Zn + S => ZnS (completed and balanced)
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Step 2
Information provided:
2.50 moles of Zn
1.00 mole of S
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Step 3
The limiting reactant limits the amount of product formed.
By stoichiometry, procedure:
Zn + S => ZnS
1 mole Zn ------------- 1 mole S
2.50 moles Zn -------------- X
X = 2.50 moles Zn x 1 mole S/1 mole Zn = 2.50 moles S
For 2.50 moles of Zn, 2.50 moles of S are needed but there is only 1.00 mole of S. Therefore, the limiting reactant is S.
Answer: Sulfur (S)