Chemical Reactions: Endothermic or Exothermic?

Chemical reactions can be categorized as endothermic or exothermic reactions. The reactions that gain energy are endothermic, whereas the exothermic reactions evolve heat. The glass of lemonade is gaining energy, thus, it is an endothermic reaction.

Condensation is the process of conversion of water vapor into liquid. In the system of glass, where water is condensed is a type of phase transition. The water molecules hit the glass (cold), give up the kinetic energy, and condense into the water droplets. Thus, the system is gaining energy and is a type of endothermic reaction.