1. Converting between Moles, Mass and Number of Particles Number of Particles to Mass Chemistry 11 Ms. McGrath

2. Number of Particles to Mass What is the mass of 5.67 x 10 24 molecules of cobalt (II) chloride, CoCl 2 ? 1.Convert the number of molecules into moles by dividing by the Avogadro’s constant. 2.Convert the number of moles into grams by multiplying it by the molar mass of cobalt (II) chloride.

3. Number of Particles to Mass 1.Convert number of particles into moles n = N N A n = 5.67 x 10 24 molecules 6.02 x 10 23 molecules / mol n = 9.42 mol

4. Number of Particles to Mass 2. Convert the moles to mass M CoCl2 = 58.93 g / mol + 2(35.45 g / mol) = 129.84 g / mol m = n x M = 9.42 mol x 129.84 g / mol = 1.22 x 10 3 g

5. Number of Particles to Mass Page 63 #28, 29, 30, 31, 32, 33 Watch the wording in #29 - 33