The elements X and Y form a compound that is 40% X and 60%Y by mass. The atomic mass of X is twice that of Y. What is the empirical formula of the compound?

Answer 1

The mass of Y is 1.5 times the mass of X in the compound, as per the percentages.

If both molecules had the same atomic mass, they would also be present in this ratio in the compound.

However, the atomic mass of X is twice that of Y. So, for the same mass, X would have half the number of atoms as Y.

Ratio of atoms of Y to that of X = Ratio of mass given * Ratio of atomic masses
= 1.5 * 2
= 3

Hence, the compound is X(1)Y(3)