Calculate the mass of calcium hydroxide obtained by interaction with water of calcium oxide weighing 16.8 grams.

Explanation of the solution to the problem: in order to solve this problem, you first need to draw up the equation of the chemical reaction: CaO + H2O => Ca (OH) 2.
Then you need to find the amount of calcium oxide substance, for this you need to divide its mass by its molar mass: n (CaO) = m / M = 16.8 / 56 = 0.3 mol.
Now you need to find the amount of calcium hydroxide substance, it is equal to the amount of calcium oxide substance, because the reaction shows that they interact in a 1: 1 ratio:
n (Ca (OH) 2) = n (CaO) = 0.3 mol.
The last step is to find the mass of calcium hydroxide, for this we multiply the found amount of calcium hydroxide substance by its molar mass:
m (Ca (OH) 2) = n (Ca (OH) 2) * M = 0.3 * 74 = 22.2 g.