ENERGY CHANGES Flashcards
What is an exothermic reaction?
A reaction which transfers heat to its surroundings (shown by rise in temperature)
What are examples of an exothermic reactions?
Combustion (burning fuels)
Hand warmers
What is an endothermic reaction?
A reaction which takes in energy from its surroundings (shown by drop in temperature)
What are examples of endothermic reactions?
Thermal decomposition
Ice packs for sport injuries
On a exothermic reaction profile, where are the reactants and products?
The reactants are higher than the products
On a endothermic reaction profile, where are the reactants and products?
The reactants are lower than the producs
What is the activation energy on a reaction profile?
The difference between the reactants and the highest point
What happens during a chemical reaction?
Old bonds are broken and new bonds are formed
What is the relationship between bonds and exothermic reactions?
Bonds are formed as energy is released
What is the relationship between bonds and endothermic reactions?
Bonds are broken as energy is supplied
What is the overall energy change?
The sum of the energies needed to break bonds in the reactants - the energy released when the new bonds are formed in the products
(energy in reactants - energy in products)
