Question

DETERMINING THE FORMULA FOR HYDRATES
HELP!!

Cocl2 ? H20
mass of hydrate :
anhydrous mass :
mass of water :
moles cocl2
moles h20
ratio:
formula
name :
I really don't get this .. can someone explain

Answer 1

I assume you have an experimental value for the mass of Hydrate and for the anhydrous mass. The difference between this two mass will be the mass of water
CoCl2 ? H20
y (58.9 + 2 (35.5)) + x (2 +16) = mass of hydrate

x = moles of H2O = mass of water/ 18
y = moles of CoCl2 = mass of anhydrous/129.9

Ratio = x/y

formula = y CoCl2 x H2O ( the most probable formula is "CoCl2 6 H2O" , but depends of your experimental data this values for x and y can be different.)

name Cobalt(II) chloride hexahydrate
if you are interested more about this compound you can consult wikipedia
http://en.wikipedia.org/wiki/Cobalt(II)_chloride

Answer 2

thank you !