Thermal decomposition of a 2-valence metal carbonate with a mass of 10 g yields 2.24 liters

Thermal decomposition of a 2-valence metal carbonate with a mass of 10 g yields 2.24 liters of carbon dioxide. Find the relative atomic mass.

1. Let’s compose the reaction equation for the decomposition of carbonate:

MeCO3 = MeO + CO2;

2.Calculate the chemical amount of carbon dioxide:

n (CO2) = V (CO2): Vm = 2.24: 22.4 = 0.1 mol;

3. Determine the amount of carbonate and find its relative molecular weight:

n (MeCO3) = n (CO2) = 0.1 mol;

Mr (MeCO3) = m (MeCO3): n (MeCO3) = 10: 0.1 = 100;

4. find the relative atomic mass of the metal:

Ar (Me) = Mr (MeCO3) – 3 * Ar (O) – Ar (C) = 100 – 3 * 16 – 12 = 40.

Answer: 40 (Ca).