How many grams of potassium hydroxide is formed when 1.5 mol of potassium oxide interacts with water?

Given:
n (K2O) = 1.5 mol

To find:
m (KOH) -?

Solution:
1) Write the equation of a chemical reaction:
K2O + H2O => 2KOH;
2) Determine the amount of KOH substance:
n (KOH) = n (K2O) * 2 = 1.5 * 2 = 3 mol;
3) 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;
4) Calculate the mass of KOH:
m (KOH) = n (KOH) * M (KOH) = 3 * 56 = 168 g.

Answer: The mass of KOH is 168 g.