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5.1 Exothermic and Endothermic Reactions - Coggle Diagram
5.1 Exothermic and Endothermic Reactions
Reaction profiles
Reaction profiles show energy changes
Exothermic reaction
The energy released from forming new bonds is greater than the energy needed to break existing bonds
Endothermic reaction
The energy needed to break existing bonds is greater than the energy released from forming new bonds
Activation energy
Chemical reactions take place when the reacting particles collide with sufficient energy
Energy change of reactions
During a reaction...
Energy must be supplied to break reactant bonds
Energy is released when products’ bonds are formed
Overall energy change is the difference between the sum of the energy needed to break reactant bonds and the sum of the energy released when products’ bonds are formed
Energy transfer
Conservation of energy
Overall amount of energy does not change
Endothermic reaction
Energy is taken in from the surroundings
Temperature of the surroundings decreases
Everyday uses
Sports injury packs
Examples
Thermal decomposition
Citric acid and sodium hydrogencarbonate
Exothermic reaction
Energy is transferred to the surroundings
Temperature of the surroundings increases
Everyday uses
Hand warmers
Examples
Many oxidation reactions
Combustion
Neutralisation
