Calculate the amount of of cobalt(II) nitrate hexahydrate [Co(NO3)2*6H2O] needed to prepare 50 mL of a .15 M cobalt(II) nitrate stock solution.

This is 2.18 g

This was diluted with deionized water in 5 different tubes

one with 1ml of Cobalt(II) Nitrate (~.15M) and 4 ml of water
2 ml--------- 3ml of water
3 ml--------- 2 ml of water
4ml ---------1 ml of water
5 ml ---------0 ml of water

1.Calculate the exact concentrations of the stock cobalt (II) nitrate solution for each of those. (Find the molarity in each of those.)

2. The molar absorpitivity (e) for Co2+(aq)