Starting with 5.00 moles of potassium sulfate and 4.00 moles of calcium nitrate, to make calcium sulfate. What reactant is the limiting reactant?

Question

K₂SO₄+Ca(NO₃)2=CaSo₄+2KNO₃

Answer 1

you can use the balanced chemical equation to see that the mole ratio between the reactants is

1 mol K₂SO₄ to 1 mol Ca(NO₃)₂, meaning that the limiting reactant will be whichever mole quantity is smaller. in this case it would be the 4.00 moles of calcium nitrate that is limiting.

Answer 2

Since the moles of reactants are given and the equation is already balanced, we can tell that Ca(NO₃)₂ is the limiting reagent.

This is because the balanced equation tells us there is a 1:1 ratio of reactants to one another; 1 mole of K₂SO₄ reacts with 1 mole of Ca(NO₃)₂ to produce 1 mole of CaSO₄ and 2 moles of KNO₃.

Since there are 5.00 moles of one reactant and 4.00 moles of the other, the greater number of moles will be present in excess and the smaller number is limiting. This would involve further calculation if the ratio of reactants were different.