Answer :
C2H4O + H2O = C2H6O2
moles water = 18 g/ 18.02 g/mol=.998
the ratio is 1 : 1 : 1
moles C2H4O needed = 0.998
mass C2H4O = 0.998 mol x 44.053 g/mol = 44.00 g
We require 44.00 g of ethylene oxide is needed to react with 18 g of water.