# How many grams of CaO to get by heating 20 grams of CaCO3, yield = 95%.

Let’s solve the problem, make up the equation:
CaCO3 = CaO + CO2 – calcium oxide is released;
Let’s calculate the molar masses of substances:
M (CaCO3) = 112 g / mol;
M (CaO) = 56 g / mol.
Determine the amount of moles of calcium carbonate, if the mass is known:
Y (CaCO3) = m / M = 20/112 = 0.178 mol;
According to the reaction equation, the amount of moles of calcium carbonate and calcium oxide is 1 mole, which means that Y (CaO) = 0.178 mole.
We find the theoretical mass of CaO:
m (CaO) = Y * M = 0.178 * 56 = 9.96 g.
We calculate the practical mass by the formula:
W = m (practical) / m (theoretical) * 100;
m (practical) = 0.95 * 9.96 = 9.46 g.
Answer: The mass of calcium oxide is 9.46 g.

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