2007-12-13 07:36:37 · 5 answers · asked by Brittney M 1 in Science & Mathematics ➔ Chemistry
To get the formula mass we have to add the atomic mass of each atom
(55.847 x 2) + ( 16 x 3) = 160
this means that 16 x 3 = 48 are the grams of O
% = 48 x 100 / 160 =30 %
2007-12-13 07:43:54 · answer #1 · answered by Dr.A 7 · 4⤊ 1⤋
The find the mass percent of oxygen, you have to determine what the mass of oxygen is. To do this, you multiply 3 moles of oxygen by 16 g/mol which is its atomic weight and you end up with 48 grams.
moles of oxygen x atomic mass = 3 x 16 = 48
The formula mass is the overall mass of the compound. Like with any percent, you divide the part over the whole and end up with 30%.
48/160 = .3 x 100% = 30%
Hope this helps!
2007-12-13 07:44:22 · answer #2 · answered by Jessy 3 · 2⤊ 0⤋
mass of oxgen in the compound=16*3=48
therefore 48/160 mutiplied by 100
=
30 percent
2007-12-13 07:41:36 · answer #3 · answered by david 1 · 2⤊ 0⤋
Fe2o3 Formula
2016-10-22 00:41:07 · answer #4 · answered by gangi 4 · 0⤊ 0⤋
Fe2O3 -- molecular mass = 159.69 g/mole
Of that 159.69 grams, 47.9982 is Oxygen (3 * 15.9994), 111.69 is Iron (2 * 55.8459)
(47.9982/ 159.69) x 100% = 30.06%
2007-12-13 07:41:07 · answer #5 · answered by Dave_Stark 7 · 2⤊ 0⤋