The thermochemical equation for the reaction in which calcium carbonate breaks down is shown below. How can the reaction be described?
CaCO,(s)+179 kg CO,(g)+ CaO(s)
A. It is endothermic.
B. It has a low activation energy.
C. It is exothermic.
D. It has a high activation energy.

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since electrons are negative the answer is neagtaive

i think it's letter a.

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.