Energetics
• standard conditions: 100kPa, 298K
"ber"
• breaking bonds = endothermic = energy is needed = temp of surroundings goes down
• examples of endothermic reactions: thermal decomposition, photosynthesis
• making bonds = exothermic = energy is released = temp of surroundings goes up
• examples of exothermic reactions: combustion, oxidation of carbohydrates
•
EineEnthalpy change = total energy absorbed - total energy released
• the same type of bond may need different amounts of energy to break, depending on its
environment; hence we use the mean bond enthalpy.
• standard conditions: 100kPa, 298K
"ber"
• breaking bonds = endothermic = energy is needed = temp of surroundings goes down
• examples of endothermic reactions: thermal decomposition, photosynthesis
• making bonds = exothermic = energy is released = temp of surroundings goes up
• examples of exothermic reactions: combustion, oxidation of carbohydrates
•
EineEnthalpy change = total energy absorbed - total energy released
• the same type of bond may need different amounts of energy to break, depending on its
environment; hence we use the mean bond enthalpy.
