Packet #4 Flashcards
kinetic energy
energy of moving objects. Energy in motion. (example: boulder falling down a hillside has a lot of kinetic energy)
potential energy
energy that is stored in objects that are not necessarily moving, but could easily start moving. (Example: boulder perched on the edge of a cliff has a lot of potential energy, even though it doesn’t have any kinetic energy).
release energy
to convert potential energy into kinetic energy (Example: When a boulder ona cliff gets knocked loose and starts to fall, potential energy is converted to kinetic energy, that is, energy is released
Absorb energy
to convert kinetic energy into potential energy (Excample: If you pick up a boulder and carry it to the top of a hill, the coulder has absorbed energy. The kinetic energy of your moving body is now stored as the potential energy the boulder has as it sits on top of the hill
Forms of kinetic energy
thermal energy, electrical currents, sound, light
chemical energy
potential energy that a chemical substance has by its very nature (fuels = high in chemical energy; Water = low in chemical energy)
kinetics
study of how fast a reaction goes
things that affect reaction rate
temperature, reactant concentration, activation energy
catalyst
a substance that speeds up a chemical reaction with being consumed in that chemical reaction. Catalyst is neither a reactant or a product
How does a catalyst affect reaction rate?
It lowers the activation energy of the reaction (speeding the reaction rate up) It lowers the activation energy by providing an alternative pathway (different mechanism) for the reaction to take place. Pathways that require less energy.
Le Chateliers principle
When a stress is applied to a system at equilibrium, the equilibrium shifts to relieve the stress
Delta H
Negative in an exothermic reaction.
Positive in an endothermic reaction
Endothermic reaction
Absorbs heat from surroundings. Delta H value is positive
After reaction, products have higher potential energy than reactants.
Absorbs more energy than is released
Exothermic reaction
Delta H is negative
Spontaneous/favorable reaction
Releases more energy than is absorbed
Products have lower potential energy than reactants at end of reaction
Chemical energy
Potential energy that a chemical substance has by its very nature
