The reaction is:
<span>4Li(s) + O2 (g) = 2Li+ + 2O-2(s).
The oxidizing agent is the one that is being reduced which is oxygen where the charge changed from neutral to -2 while the reducing agent is the on being oxidized which is lithium where the charge change from neutral to +1.</span>
<span>Endothermic Reaction. This reaction or process absorbs energy from its surroundings, mostly, but will not always be, in form of heat. A reaction that requires the input of energy that breaks a bond will always be endothermic. Best examples of endothermic reaction are: 1) melting cubes; 2) evaporating of liquid; 3) melting solid salts, etc.</span>