rates and equilibrium Flashcards
Define heat of reaction (^H)
The energy absorbed or released in a chemical reaction
Define exothermic reaction
Reaction that releases energy
Define endothermic reaction
Reaction that absorbs energy
Heat of reaction for endothermic reaction
^H > 0
Heat of reaction for exothermic reaction
^H < 0
Define activation energy
Minimum energy needed for a reaction to take place
Define an activated complex
The unstable transition state from reactants to products
Bond energy
Minimum amount of energy (in kJ or kJ.mol-1) required to break a bond
Bond energy also called
Bond dissociation energy
Bond energy represented by
D
What happens when a bond is broken?
Energy is absorbed to overcome intramolecular forces - bond energy
Hence, what is the breaking of a bond
Endothermic reaction
Hence, what is the formation of a bond
Exothermic reaction
What does this mean for the energy state of the system before and after the reaction?
Energy change
How is the energy change determined**
^H = Hi
(sum of bond energies of each reactant) - (sum of bond energies of each product)
