Unit: Chemical Quantities Two-step Conversions: Particles to Mass and Vice Versa After today, you will be able to… • Perform two-step conversions using molar mass and representative particles (atoms, molecules, and formula units) We have already learned… How to convert moles into particles and vice versa by using the conversion factor… 1 mole = 6.02x1023 particles How to convert moles into grams and vice versa by using the conversion factor… 1 mole = atomic mass in grams These two conversion factors can now be combined… Particles Moles Grams 6.02x1023 molar mass Grams Moles Particles molar mass 6.02x1023 Example: What is the mass of 1.79x1024 formula units of K3PO4? K: 1.79x1024 F.U. K3PO4 U: ? g K3PO4 1.79x1024 F.U. K3PO4 x 1 3 K = 3(39.10) = 1 P = 1(30.97) = 4 O = 4(16.00) = 117.30 30.97 +64.00 212.27 1 mol K3PO4 x 212.27 g K3PO4 = 6.02x1023 F.U. K3PO4 1 mol K3PO4 . . 631 g K3PO4 Time to Practice! Complete WS 3