This is an example of an esterification reaction where one molecule acetic acid (also called ethanoic acid) reacts with one molecule ethanol, yielding one molecule ethyl acetate (a bimolecular second-order reaction of the type A + B → C):
: 120 g acetic acid (60 g/mol, 2.0 mol) was reacted with 230 g ethanol (46 g/mol, 5.0 mol), yielding 132 g ethyl acetate (88 g/mol, 1.5 mol). The yield was 75%.
# The molar amount of the reactants is calculated from the weights (acetic acid: 120 g ÷ 60 g/mol = 2.0 mol; ethanol:  230 g ÷ 46 g/mol = 5.0 mol).
# Ethanol is used in a 2.5-fold excess (5.0 mol ÷ 2.0 mol).
# The theoretical molar yield is 2.0 mol (the molar amount of the limiting compound, acetic acid).
# The molar yield of the product is calculated from its weight (132 g ÷ 88 g/mol = 1.5 mol).
# The % yield is calculated from the actual molar yield and the theoretical molar yield (1.5 mol ÷ 2.0 mol × 100% = 75%).