How many grams of cuso4 are there in 100.0 g of hydrate? how many moles?

The hydrate form of CuSO4 has 5 water molecules (CuSO4-5H20) copper (II) Sulfate pentahydrate or commonly known as blue vitriol. 

To solve, the following molar masses are to be known. 
CuSO4.5H2O (hydrate)  - 249.7g/mole
CuSO4 (anhydrous) -159.6g/mole
Also there molar ratio of the hydrate and CuSO4 is 1. 

the mass of the hydrate is to be divided by the molar mass of the hydrate then multiplied by the ratio (1) to get the moles of hydrate and multiplied by the molar mass of the anhydrous to get the mass in grams. 

moles = (100g/249.7)*1 =  0.4 moles hydrate
grams = 0.4*159.6 =  64.9 grames hydrate

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer