Question

Simplest formula of compound containing 21.9 percent of magnesium, 27.8percent of phosphorus, 50.3percent of oxygen

Answer 1

o2mg2k3 ...............

Answer 2

you must start by dividing each % amount by atomic mass of the element

Mg=21.9/24.3

=0.9012

P=27.8/31

=0.896

O=50.3/16

=3.14

divide through by smallest value

Mg=0.9012/0.896

=1

P=0.896/0.896

=1

O=3.14/0.896

=3.5

multiply by 2 to remove fraction

Mg=2

P=2

O=7

hence empirical formula=Mg2P2O7