what is the gram formula mass of CaSO4*2H20?

5 answers

Look up the masses on the periodic table and add them.
1 Cu
1 S
4 O
5 H2O
i got 112.61 is that right ?
No. I've rounded below but you need to do it more accurately; how accurately depends upon your instructions.
Cu = about 63
S = about 32
O = 16*4 = 64
5 H2O = 5*(2+16) = about 90.
All of that adds up to more than 112.
Why did you use Cu instead of Ca
CaSO4
Ca=40
S=32
O=16x4
40+32+16×4
416amu