Percent composition by mass of oxygen =
((16.0*6)/(40.1+2*(14.0+16.0*3)))*100%
= 58.5%
therefore, the answer is D
Answer:
I think section #3
Explanation:
When i was in science class in my memory it was always in that area
The number of moles of moles of Magnesium,chlorine and oxygen atoms in 7.80 moles of Mg(ClO4)2 is calculated as below
find the total number of each atom in Mg(ClO4)2
that is mg = 1 atom
Cl = 1x2 = 2 atoms
O = 4 x2 = 8 atoms
then multiply 7.80 moles with total number of each atom , to get the number moles of each atom
that is
Mg = 7.80 x1= 7.80 moles
cl = 7.80 x2=15.6 moles
O = 7.80 x8= 62.4 moles
