4.5 Energy Changes Flashcards
What happens to the energy before and after a reaction
It is the exact same
What happens to the energy of the products when energy is transferred to the surroundings
Product molecules have much less energy than the reactions - by the amount that is transferred
Exothermic reaction
Energy transferred to the surroundings (surroundings temp. increased)
Endothermic reaction
Energy transferred from the surroundings to the products.
Examples of exothermic reactions:
Combustion, oxidisation, neutrilisation, self heating cans, hand warmers
Examples of endothermic reactions:
Thermal decomposition, citric acid and sodium hydrogencarbonate, cold packs
Minimum energy required for a reaction to occur
Activation energy
Where is the reactants on an energy level diagram of an exothermic reaction
Above the products
Where is the reactants on an energy level diagram of an endothermic reaction
Below the products
Reactants above products in energy level diagram
Exothermic
Reactants below products in energy level diagram
Endothermic
