When do changes in heat energy occur
-salts dissolving in water
-neutralising reactions
-displacement reactions
-precipitation reactions
What is an exothermic change
a reaction in which heat is given out
What is an endothermic change
a reaction in which heat energy is taken in
What is the breaking of bonds
endothermic
What is the making of bonds
exothermic
When is a reaction endothermic
if less heat energy is released in forming bonds in the products than is required in breaking bonds in the reactants
When is a reaction exothermic
if more heat energy is released in forming bonds in the products than is required in breaking the bonds in the reactants
What is activation energy
the minimum amount of energy that colliding reactant particles need to possess for a successful collision, allowing them to overcome the energy barrier and transform into products
What is energy change measured in
KJmol^-1
