Question

What is the molecular formula of a substance that has an empirical formula of C2H5 and a molecular mass of 58 g/mole?

Answer 1

The empirical formula is always a multiple of the empirical formula, but remember the multiple may be `1`.

Explanation:

So `MF=(EF)xxn`. Thus `[2xx12.011*g*mol^(-1)+ 5xx1.00794*g*mol^(-1)]xxn=58*g*mol^(-1).`

It does not take much algebra to find that `n` `=` `2`.

Thus the molecular formula `=` `2xxC_2H_5` `=` `C_4H_10`, butane.