1. this energy diagram is for the thermal decomposition of solid mercury (ii) oxide (also known as mercuric oxide) into liquid mercury and oxygen gas. • write a balanced equation for the reaction. • explain what feature is shown by the arrow labeled (a). • using chemical symbols and dashed lines (this can be done with type), draw what the activated complex or transition state might look like. • is this reaction exothermic or endothermic? explain.

The term endothermic process describes a process or reaction in which the system absorbs energy from its surroundings; usually, but not always, in the form of heat. ... The opposite of an endothermic process is an exothermic process, one that releases, "gives out" energy in the form of heat. so as i have verified for you plz note that the anwser to your questio (Is this reaction exothermic or endothermic? ) it is exothermic thanks plz make brainliest and give a rating

It would be (at) + cu (s)