posted by Lola on .
Chromium (II) nitrate forms a hydrate that is 40.50% water by mass. What is its chemical formula?
I just need to figure out how to do it!
Cr(NO3)2.xH2O. You want to determine the value of x.
Take a 100 g sample which will give you
40.5 g H2O and
59.5 g Cr(NO3)2
Convert to moles.
40.5/molar mass H2O = ??
59.5/molar mass Cr(NO3)2
Now find the ratio of H2O molecules to 1 molecule Cr(NO3)2.
Check your numbers; this doesn't come out as well as I think it should. Check my work; perhaps I made an error.