The molar mass of ammonium acetate is 77.083 g/mol. A student uses 0.100 mol of ammonium acetate in a chemical reaction. The student claims that the reaction uses (0.100 mol)(77.083 g/mol)=7.71 g of ammonium acetate, which has
(7.71)(6.022×10^23)=4.64×10^24 molecules. In one to two sentences, explain the mistake that the student made and determine the correct number of molecules of ammonium acetate used in the reaction.
The mistake the student made is that they incorrectly multiplied the number of moles by Avogadro's number. To determine the correct number of molecules, they should have multiplied the number of moles by Avogadro's number first, and then multiplied by the molar mass. Thus, the correct number of molecules used in the reaction is (0.100 mol)(6.022×10^23 molecules/mol) = 6.022×10^22 molecules.
