Calculate ion concentration. In the laboratory, a student adds 12.7 g of chromium(II) nitrate to a 125 mL volumetric flask and adds water to the mark on the neck of the flask. Calculate the concentration (in mol/L) of chromium(II) nitrate, the chromium(II) ion and the nitrate ion in the solution.

[Cr(NO3)2] = M

[Cr2+] = M

[NO3-] = M