How many grams of KOH do you need to dissolve in water to get 200 ml of a 2N solution?

Given:
V solution (KOH) = 200 ml = 0.2 l
SN (KOH) = 2 n

Find:
m (KOH) -?

Solution:
1) Calculate the amount of substance KOH:
n (KOH) = CH (KOH) * V solution (KOH) / z = 2 * 0.2 / 1 = 0.4 mol;
2) Using the periodic system of D.I.Mendeleev, calculate the molar mass of KOH:
M (KOH) = Mr (KOH) = Ar (K) * N (K) + Ar (O) * N (O) + Ar (H) * N (H) = 39 * 1 + 16 * 1 + 1 * 1 = 56 g / mol;
3) Calculate the mass of KOH:
m (KOH) = n (KOH) * M (KOH) = 0.4 * 56 = 22.4 g.

Answer: The mass of potassium hydroxide is 22.4 g.