What does an Exothermic reaction do?
Releases heat energy to surroundings
🔺H is negative
What does an Endothermic reaction do?
Absorbs heat energy from surroundings
🔺H is positive
What are examples of Exothermic and Endothermic reactions?
Exothermic:
Combustion, Respiration
Endothermic:
Thermal decomposition, cracking
What does an exothermic energy profile show?
Show energy changes during reactions.
Products lower than reactants
Activation energy is the energy needed to start reaction
What does an endothermic energy profile show?
Shows energy changes during reactions
Products higher than reactants Activation energy is the energy needed to start a reaction
What is the unit for Enthalpy change?
kJ mol^-1
Define enthalpy change
When 1 mole of substance completely burns in oxygen
How do you measure enthalpy change of combustion?
Use calorimeter to measure temperature change of water heated by fuel
