In a lab, .0092 moles of Cu were reacted with .0046 miles of S. What would happen to the mole Cu/mole S ratio if some of the copper was unreacted (increase, decrease, stay the same)?

Question

In a lab, .0092 moles of Cu were reacted with .0046 miles of S.  What would happen to the mole Cu/mole S ratio if some of the copper was unreacted (increase, decrease, stay the same)?

Also, what will happen to the mole Cu/ Mole S ratio if unreacted sulfur remains in the crucible when the final weighing is made (increases, decreases, stays the same)?

GK · Answer

Is the question about the mole ratio in the product or the mixture??
If the product is CuS, the mole ratio in the product is 1molCu/1molS=1 molCu/molS
The mole ratio of the masses of the elements in any compound is definite, not dependent on the reactants ratio in making it.