How many grams of CoCl2 do you need to take to prepare 200 ml 0.2N. CoCl2 solution?

Given:
V solution (CoCl2) = 200 ml = 0.2 l
Cn (CoCl2) = 0.2 n

To find:
m (CoCl2) -?

Decision:
1) Calculate the amount of substance CoCl2:
n (CoCl2) = CH (CoCl2) * V solution (CoCl2) / z = 0.2 * 0.2 / 2 = 0.02 mol;
2) Using the periodic system of D.I.Mendeleev, calculate the molar mass of CoCl2:
M (CoCl2) = Mr (CoCl2) = Ar (Co) * N (Co) + Ar (Cl) * N (Cl) = 59 * 1 + 35.5 * 2 = 130 g / mol;
3) Calculate the mass of CoCl2:
m (CoCl2) = n (CoCl2) * M (CoCl2) = 0.02 * 130 = 2.6 g.

Answer: The mass of CoCl2 is 2.6 g.