7. Energetics Flashcards
What does endothermic mean?
Energy is absorbed (by a reaction)
What does exothermic mean?
Energy is released (by a reaction)
What happens when bonds are made?
Energy is released
What happens when bonds are broken?
Energy is absorbed
Why are some reactions exothermic?
More energy is released when bonds are made that required to break them.
Net release of energy
Why are some reactions endothermic?
Less energy is released when bonds are made that required to break them
Net absorption of energy
What are examples of exothermic reactions?
Combustion (oxidation)
Acid + base (metal, oxide or carbonate) In most cases
What are products that use exothermic reactions?
handwarmers
self heating cans
What are examples of endothermic reactions?
Thermal decomposition
Dissolving ammonium nitrate in water
What are products that use endothermic reactions?
sports injury cool packs
Exothermic reactions makes the mixture feel…
hotter and energy is transferred to the surroundings
Endothermic reactions makes the mixture feel…
cooler and energy is transferred from the surroundings
What is the activation energy?
Energy required by the reactants to ensure that there is a successful reaction
Energy required to break sufficient bonds for a reaction to occur
In a exothermic reaction the products have…
less energy than the reactants
In a endothermic reaction the products have…
more energy than the reactants
