# When 100 g of sodium carbonate is heated, a basic oxide with a mass of …

September 30, 2021 | education

| Let’s write the reaction equation:

Na2CO3 = Na2O + CO2

Let’s write an expression to determine the amount of a substance:

ν = m / M

We have the amount of sodium carbonate and oxide substances are equal, judging by the reaction equation:

m (Na2CO3) / M (Na2CO3) = m (Na2O) / M (Na2O)

Let’s define the molar masses:

M (Na2CO3) = 22.9 * 2 + 12 + 16 * 3 = 105.8 g / mol

M (Na2O) = 22.9 * 2 + 16 = 61.8 g / mol

Let us express the mass of the oxide from the previous formula:

m (Na2O) = m (Na2CO3) * M (Na2O) / M (Na2CO3)

Substitute the numerical values:

m (Na2O) = 100 * 61.8 / 105.8 = 56

Answer: the mass of the oxide is 56 g.