Exothermic and Endothermic Reactions Flashcards
Chemical Energy
-energy stored in the chemical bonds of a substance
-chemical reactions always involve energy changes
-making bonds and breaking bonds involve energy changes
Activation Energy
the energy required to break the bonds in the reactants for a chemical reaction to occur
How to identify if a reaction is exothermic?
If more energy is released than supplied
How to identify if a reaction is endothermic
if more energy is supplied than is released
Exothermic or Endothermic
based on the type of energy (heat) change involved, chemical reactions are classified as either Exothermic or Endothermic
Exothermic
-energy is released
-heat (energy) given off
-temperature of the substance rises
-products feel hot
Endothermic
-energy is absorbed
-heat (energy) taken in
-temperature of the substance drops
-products feel cold
endothermic reactions
reactants + energy = products
reactants + heat = products
endothermic formula
6CO2 + 6H2O + Energy - C6H12O6 + 6O2
exothermic formula
CH4 + 2O2 - CO2 + 2H2O + Energy
Example of exothermic
-combustion of fuels
-yeast & hydrogen peroxide
-Epson salts & water
Example of endothermic
-photosynthesis
-acidic acid & sodium bicarbonate