Amixture of ethyl iodide (c2h5i, bp 72.3°c) and water boils at 63.7°c. what weight of ethyl iodide would be carried over by 1 g of steam during steam distillation?

You only need to know first is the vapor pressure of water at that boiling point which is ~ 179 mm hg.

 So the (vapor pressure of C2H5I = 760 – 179)

And since you know the molecular weight of H2O which is equal to18 g/mol and the molecular weight of C2H5I = 156 g/mol.

Just apply the equation: 

grams H2O M.W.      H2O × P H2O 

    = =  28.13 grams C2H5I 

grams C2H5I M.W.   C2H5I × P C2H5I

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.