Atomic mass of #X# = 75

Percentage of #X# = 75.8%

Atomic mass of #Y# = 16

Percentage of #Y# = (100-75.8)% = 24.2%

Divide each percentage by the correlating mass:

#X# - #(P_X)/(M_X)=75.8/75~~1#

#Y# - #(P_Y)/(M_Y)=24.2/75~~1.5#

The ratio of #X:Y = 1:1.5#, but you can't have #1/2# an atom in a molecule, so the ratio must be doubled so #X:Y=2:3#.

The empirical formula = #X_2Y_3#

Proof:

For X - #"Percentage of mass composition" = ("Mass contributuon")/("Total mass")*100 = (2(75))/(2(75)+3(16))*100 = 75.7575... =75.8%#.

For Y - #"Percentage of mass composition" = ("Mass contributuon")/("Total mass")*100 = (3(16))/(2(75)+3(16))*100 = 24.2424... =24.2%#.