Question

At high temperatures, calcium carbonate (CaCO3) decomposes to form calcium oxide (CaO) and carbon dioxide (CO2) gas. The average mass of 1 calcium oxide molecule is 56.079 amu, and the average mass of 1 carbon dioxide molecule is 44.009 amu.

CaCO3 CaO + CO2
Which is the total mass of the 1 calcium carbonate molecule?
A. 12.070 amu
B. 44.009 amu
C. 56.079 amu
D. 100.088 amu

Answer 1

The total mass of the 1 calcium carbonate molecule is 100.088 amu

Explanation

CaCO3 → CaO + Co2

According to law of mass conservation in a chemical reaction the mass of the product must be equal to mass of product.

In reaction of decomposition of CaCO3, CaCo3 is the reactant while CaO and Co2 are the products

Therefore the mass of CaCO3 must be equal to mass of CaO +CO2

mass of CaO + CO2 = 56.079 amu + 44.009 amu = 100.088 amu

The mass of CaCo3 is therefore = 100.088 amu