Question

Cu = 61.37% and O = 38.63%.

What will be the empirical formula based on these mass percent values?

Answer 1

Let the numbers of Cu and O atoms in the empirical formula be x, y, respectively.

Atomic masses

Ar(Cu)=63.5

Ar(O)=16

$$X:Y=\omega(X)/A(X):\omega(Y)/A(Y)$$

$$X:Y=(61.37/63.5):(38.63/16)$$

$$X:Y=0.97:2.4=1:2.5=2:5$$

Empirical formula Cu2O5