In the following equations, determine which reactant is the limiting reactant and which reactant is in excess.? The amounts mixed together are shown below each reactant. a) 2NaOH(10g) + H2SO4(10g) →Na2SO4+2H2O

1 Answer
Jul 31, 2017


Use the given masses to calculate the Moles of each compound. Use the moles to see which one will "run out" first. It is the limiting reagent.


Chemistry occurs in MOLE quantities. Masses (weights) are what we measure. So, to calculate reactions we need to put everything into terms of Moles before we can solve them. We also need to BALANCE the chemical reaction correctly. Then the ratio of moles of each substance can readily be seen.

The "limiting" reagent is simply the one that runs out first, and the "excess" is the one that is left over after the limiting reagent has been completely used up.

If the equation molar ratios are 2:3, and only 1 of the first is available, it is the limiting reagent, and it will be consumed when only 1.5 of the other is used. Thus, the second one is the "excess reagent" and will have 1.5 moles left in the solution after the first reagent is gone.