# Doused with water 7 gr. calcium oxide. How much calcium hydroxide Ca (OH) 2 is obtained from this?

To solve, we write down the reaction equation:
CaO + H2O = Ca (OH) 2 – compound reaction, calcium hydroxide is obtained;
Let’s calculate the molar masses of substances:
M (CaO) = 40 + 16 = 56 g / mol;
M (CaCO3) = 40 + 17 * 2 = 74 g / mol;
Determine the amount of moles of calcium oxide, if its mass is known:
Y (CaO) = m / M = 7/56 = 0.125 mol;
Let’s make the proportion:
0.125 mol (CaO) – X mol of Ca (OH) 2;
-1 mol -1 mol hence, X mol of Ca (OH) 2 = 0.125 * 1/1 = 0.125 mol;
We calculate the mass of calcium hydroxide by the formula:
mCa (OH) 2 = Y * M = 0.125 * 74 = 9.25 g.
Answer: during the reaction, calcium hydroxide with a mass of 9.25 g is released.

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