Using Conversions

Avogadro’s Number The SI unit for amount is called the mole (mol). 1 mole = 6.02 x 1023 particles Particles can be: ●atoms (Na, Fe, Cu) ●ions (Na+, Fe3+, Cu2+) ●molecules (covalent, diatomic) ●formula units (ionic)

Converting molar mass/moles 1 mole X # grams X # grams X 1 mole X X = symbol/formula # = molar mass

1) Given 2) Use molar mass 1 mol Cu = 63.55 g Cu 75.92 g Cu x Example: Determine the number of moles in 75.92 g of copper. 1) Given 2) Use molar mass 1 mol Cu = 63.55 g Cu 75.92 g Cu x 1.195 mol Cu 3) Solve, round answer using sig.figs

1) Given 2) Use molar mass 58.44 g NaCl= 1 mol NaCl 154 g NaCl Example: Find the mass of 2.64 mole of sodium chloride. 1) Given 2) Use molar mass 58.44 g NaCl= 1 mol NaCl 154 g NaCl 2.64 mol NaCl x 1 Na = 22.99 g 1 Cl = 35.45 g 3) Solve, round answer using sig.figs

Converting Avogadro’s Number/ moles 6.02 x 1023 ? 6.02 x 1023 ? 1 mole ? ? = type of particle

Example: Convert 2.66 mol of a sodium into atoms. 1) Given 2) Use Avogadro’s # 6.02 x 1023 atoms Na = 1mol Na 2.66 mol Na x 1.60 x 1024 atoms Na 3) Solve, round answer using sig.figs

2) Use Avogadro’s # 1) Given 2.54 x 1022 ions Fe3+ x Example: How many moles are 2.54 x 1022 iron(III) ions? 2) Use Avogadro’s # 1) Given 1 mol Fe3+ = 6.02 x 1023 ions Fe3+ 2.54 x 1022 ions Fe3+ x 0.0422 mol Fe3+ 3) Solve, round answer using sig.figs