how many atoms of iron are in .0750 moles of the compound Iron(III) oxide?
Fe2O3 my guess is .375 am I right .750/2=.375
No, don't guess.
The molar mass of Fe2O3 is approximately 159. You should look up the molar mass and use the exact number. 159 grams (1 mol) Fe2O3 will contain 6.02x 10^23 molecules. So you have 0.0750 mols and that should contain 0.0750 mols x 6.02 x 10^23 molecules/mol = ?? molecules Fe2O3.
Since there are 2 atoms of Fe per mole of Fe2O3, then 2x?? will be the number of atoms Fe. Check my thinking.
molar mass is 160g. its really .750 not 0.0750 sorry. and i multiplied .750 by 6.02 x 10^23 and multiplied THAT by 2 and got 9.03 x 10^23. is that it?
That is correct.
Yes, that is correct! Since the molar mass of Fe2O3 is 160 grams (according to your correction), you have 0.750 moles of Fe2O3. By multiplying 0.750 moles by Avogadro's number (6.02 x 10^23 molecules/mol), you get the number of molecules of Fe2O3, which is 4.515 x 10^23 molecules.
Since there are 2 atoms of Fe per molecule of Fe2O3, you multiply the number of molecules by 2 to get the total number of iron atoms. Thus, 4.515 x 10^23 molecules multiplied by 2 equals 9.03 x 10^23 atoms of iron in 0.750 moles of Fe2O3. Well done!