1. Mole Problems

2. Mass Mole Particles Always 6.02 x 1023 part = 1 mole Molar mass (g)
Avogadro’s #
Mass
Mole
Particles
(atoms, molecules, ions, etc)
(g)
(mol)
Molar mass comes from the Periodic Table
Always
6.02 x 1023 part = 1 mole

3. How many grams are in 2.0 moles of calcium?
So, where are you starting and finishing? Moles  Mass (need the molar mass of Ca) 2.0 mol Ca X
80.16 g Ca so it becomes 80. g Ca
(2)

4. How many moles are in 25.0 grams of calcium metal?
Going from mass  moles
0.624 mol Ca
This time the molar mass is on the bottom to cancel out the (g) we started with

5. How many grams of iron are present in 4.24 x 10 23 iron atoms?
Going from parts  moles  mass
39.3 g Fe

6. Compounds are no different
How many particles are in 40.0 grams of sodium chloride (58.44 g/mol)?
Molar mass of NaCl
4.12 x 1023 NaCl particles