We divide thru the molar quantities by the SMALLEST such molar quantity, that of nitrogen:
$C: (0.175*mol)/(0.035*mol)$ $=$ $5$
$H: (0.140*mol)/(0.035*mol)$ $=$ $4$
$N: (0.035*mol)/(0.035*mol)$ $=$ $1$.
And thus we get an empirical formula of $C_5H_4N$.
But the molecular formula is always a whole number mulitple of the empirical formula:
$"(molecular formula)"="n"xx"(empirical formula)"$
And then solve for $"n".$
$160*g*mol^-1$ $=$ $nxx(5xx12.011+4xx1.0076+14.01)*g*mol^-1$.
By this calculation, the empirical mass is $78*g*mol^-1$. This is tolerably close to half the measured molecular mass. Thus $n~=2$. This often occurs if the molecular mass has to be estimated by more traditional means than mass spectroscopy, i.e. boiling point elevation, or by the isopiestic method.
Thus $"molecular formula"=C_10H_8N_2$
