During the Intensive Revision Bootcamp, the concepts surrounding the chapter on Energy Changes (Endothermic/Exothermic) are dissected and the correct concepts are shared with the class.This chapter requires little memorization and in fact, 95% of the chapter involved the understanding of the concepts and applying them accordingly in application questions, especially for those that involves Bond-Forming & Bond-Making.
First we need to define Exothermic and Endothermic properly.
Exothermic Reactions:
– Reactions that gives out heat energy to the surroundings
– T of reaction mixture rises. Container feels hotter
Endothermic Reactions:
– Reactions that takes in heat energy from the surroundings
– Temperature of reaction mixture falls. Container feels cold.
Energy changes in reactions are caused by the making & breaking of chemical bonds
? Bond Making –> Exothermic Process
? Bond Breaking –> Endothermic Process
Tell if a Reaction is Exothermic or Endothermic by:
? Exothermic Reaction:? ?H bond breaking < ?H bond making
? Endothermic Reaction:? ?H bond breaking >? ?H bond making
Q) Is this reaction Exothermic or Endothermic then? What is the value of Enthalpy Change?
Given:
Cl-Cl bond energy = 242 kJ/mol
H-H bond energy = 436 kJ/mol
H-Cl bond energy = 431 kJ/molAny takers? Write down your suggested answers in the Comment section below, and we will discuss it accordingly.
PS: Once again –> Participation is Impt! No point me showing you all the answers and working, and u dont learn.