Moles and Stoichiometry:
$\therefore$ the empirical formula of the hydrated compound is $CuSO_4.7H_2O$
%C = 40% %H = 6.7% %O = 53.3%
Post-writing Commentary Empirical formula sucks :( I mean its still my fault for thinking a hydrated salt can exist as 2: $Al(NO_3)
3$ to 31: $H{2}O$ or something like that
