Question

In a compound AB3 , the element B has an average atomic mass that is 0.389 times the average atomic mass of element A. For every 1.000 g of element A in the compound, there will be _____ g of element B, if the compound is pure.

Answer 1

For one atom of A there are 3 atoms of B in compound AB3.

Average atomic mass of B is 0.389 times the average atomic mass of element A.
, then for 1 g of A there must be 3*0.389g of B
=1.167g of B