Question

what is an exothermic reaction? which of the following is an exothermic reaction
a.. heating calcium carbonate
b.. adding water to calcium oxide ​

Answer 1

Answer:

The opposite of endothermic is exothermic; in an exothermic reaction, energy as heat is evolved. ... The formation of slaked lime (calcium hydroxide, Ca(OH)2) when water is added to lime (CaO) is exothermic.

Formation of water from molecular hydrogen and oxygen and the formation of a metal oxide such as calcium oxide (CaO) from calcium metal and oxygen gas are examples. Among widely recognizable exothermic reactions is the combustion of fuels (such as the reaction of methane with oxygen mentioned previously).

Answer 2

Explanation:

The reaction which are accompained by the evolution of heat,are called exothermic reaction

Or

the reactions in which heat is released alongwith the formation of products are called exothermic reactions

a) heating calciumcarbonate is an exothermic reation