+509 1. How many moles of gold are in 2.23 X 10^17 atoms of gold?
2. How many moles of rust (Fe2O3) are in 9.21 X 10^27 formula units of the compound?
3. How many atoms of pure copper are in 1.95 mol of copper?
+128407 I can do the first one
2.23 x 10^17 x 1 mole
________________ =
6.0221415 × 10^23
2.23 x 10^17
_______________ moles =
6.0221415 × 10^23
0.3703001664773237 x 10^(17 - 23) ≈ .37 x 10^(-6) = 3.7 x 10^(-7) moles
+36915 2. The formula unit for rust is as given....
9.21 x 10^23 molecules / 6.02214 x 10 ^23 molecules/mole = 1.529 moles of rust formula units
3. 1.95 mole x 6.022 x 10^23 atoms/mole = 11.743 x 10^23 atoms
( I would recommend counting them all just to be sure! ) 
2)
EP: Did you mean to: convert 9.21×10^27 molecules of iron(III) oxide to moles? If so, then:
9.21 x 10^27 / 6.022...x 10^23 =15,294 moles.
+36915 Yes, that is what I meant to do......but I typed in the incorrect number for the rust units ....it should be 10^27 not 10^23, so the answer is 100000 times bigger.....sorry. And thanx!
9.21 x 10^27 molecules / 6.02214 x 10 ^23 molecules/mole = 15290 moles of rust formula units
