Question

If 2.0 moles of A and 3.0 moles of B react according to the hypothetical reaction below, how many moles of the excess reactant will be left over at the end of the reaction?

Answer 1

A + 2B → AB2

1.0 mol B left over

0.50 mol A left over

1.5 mol B left over

1.5 mol A left over

Answer 2

There would be 0.50 mol A left over. Because of the mole ratios, when 1.5 moles of A is used, all 3 mol of B has been used.