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.)

1. Two water molecules contain 4 hydrogen atoms and 2 oxygen atoms. A mole of water molecules contains 2 moles of hydrogen atoms and 1 mole of oxygen atoms.

2. 12.00 g C-12 = 1 mol C-12 atoms = 6.022 × 1023 atoms • The number of particles in 1 mole is called Avogadro's Number (6.0221421 x 1023). Calculate the number of atoms in 2.45 mol of copper.

That’s all I know I think