Final answer:
The chemical reaction involving 20.0 g of solid calcium carbonate is A. decomposition reaction, where calcium carbonate decomposes into calcium oxide and carbon dioxide when heated.
Step-by-step explanation:
The question appears to be asking about the classification of a chemical reaction involving calcium carbonate (CaCO3). In this context, the reaction being referred to is the decomposition of calcium carbonate when heated to form calcium oxide (CaO) and carbon dioxide (CO2).
Decomposition reactions involve a single compound breaking down into two or more products. This is in contrast to synthesis reactions where multiple reactants combine to form a single product, combustion reactions that typically involve a compound reacting with oxygen to produce oxides and release energy, and precipitation reactions where a solid product forms from the reaction of two solutions.
Example 3.7.1 illustrates that when 10.0 grams of calcium carbonate (CaCO3) are heated, they produce 4.4 g of carbon dioxide (CO2) and 5.6 g of calcium oxide (CaO), thus confirming the law of conservation of mass.
Similarly, if 20.0 grams of calcium carbonate were subjected to heating, it would also undergo a decomposition reaction, not a precipitation, combustion, or synthesis reaction. Therefore, the correct option to describe this chemical process is decomposition, which would be option A in the list provided in the question.