Posted by Melissa on .
I am really having trouble answering this question, can someone help?
A binary compound between an unknown element E and hydrogen contains 91.27% E and 8.73% H by mass. If the formula of the compound is E3H8, calculate the atomic mass of E.

Chemistry 
DrBob222,
I think I would do this.
If the compound is E3H8, it must be E1H2.667.
91.27/atomic mass E = ??
8.73/atomic mass H = 8.73
To make 8.73=2.667, the divisor must be
8.73/2.667 = 3.27; therefore, the divisor for 91.27 must be 3.27.
91.27/3.27 = 27.9 for the atomic mass E.
I assume the compound is Si3H8.
Check my thinking.