[afchick7689]

The problem reads:

A 1.0 g sample of the hydrate COSO₄ x H₂O gave on heating, 0.55 g of the anydrous salt, cobalt II sulfate.  What is the formula for the hydrate?

And my work is below-- i just had to teach myself the process for this one, so i wanted to make sure there weren't any errors I overlooked...

(CoSO4)x ? (H2O)y
Molar mass of hydrate: 58.933 + 32.065 + (16*4) = 154.998
Molar mass of water: 1.01*2 + 16 = 18.02
mass of hydrate used: 1.0g
mass of anhydrous salt left behind: 0.55g
mass of water left behind: 1.0 g - 0.55 g = 0.45g
moles of anhydrous salt present in hydrate: 0.55g/ 154.998g/mol = 0.0035484 mol
moles of water present in hydrate: 0.45g/ 18.02g/mol = 0.024972 mol
((Divide by smallest mole (0.0035484):
salt: 0.0035484 mol / 0.0035484 mol = 1
water: 0.024972 mol / 0.0035484 mol = 7.037 = 7
(CoSO4) ? (H2O)7

-thanks!!

[xiankai]

nothing wrong as far as i can see

u dont have to put the compound in brackets, though. also, put the molar fraction in front of the compound, so it reads something like CoSO4.7H2O