1. How many atoms are in 2.15 moles of water?

*2. How many atoms of copper are in 12.0 grams?

*3. How many moles of NH3 contain 1.75 x 10^24 molecules of?

4. Determine the number of molecules in 16.75 g of H2O ?

5. Find the formula for a hydrate with 48.8% MgSO4 & 51.2% H2O

6. What is the % by mass of C in Pb(C2H3O2)2?

(Questions with stars just don't make sense to me.)