What mass of calcium oxide (CaO) will be obtained by decomposition of 50 g of calcium carbonate?

Given:
m (CaCO3) = 50 g

Find:
m (CaO) -?

Solution:
1) Write the reaction equation:
CaCO3 = (tOC) => CaO + CO2 ↑;
2) Calculate the molar masses of CaCO3 and CaO:
M (CaCO3) = Mr (CaCO3) = Ar (Ca) + Ar (C) + Ar (O) * 3 = 40 + 12 + 16 * 3 = 100 g / mol;
M (CaO) = Mr (CaO) = Ar (Ca) + Ar (O) = 40 + 16 = 56 g / mol;
3) Calculate the amount of CaCO3 substance:
n (CaCO3) = m (CaCO3) / M (CaCO3) = 50/100 = 0.5 mol;
4) Determine the amount of CaO substance:
n (CaO) = n (CaCO3) = 0.5 mol;
5) Calculate the mass of CaO:
m (CaO) = n (CaO) * M (CaO) = 0.5 * 56 = 28 g.

Answer: The mass of CaO is 28 g.