energy diagrams Flashcards
activation energy
the minimum energy required by reactants for a reaction to occur; symbol Ea .
This energy is needed to break the bonds between atoms in the reactants to allow products to form.
chemical energy
form of energy stored in the chemical bonds between atoms and molecules.
This energy results from attractions between electrons and protons in atoms;
repulsions between nuclei (+)
repulsions between electrons (-)
movement of electrons
vibrations and rotations around bonds
chemiluminescence
light emitted by a chemical reaction
decomposition
a reaction in which a compound is broken down into smaller parts.
endothermic
a reaction that absorbs net energy from the surroundings,
i.e. ^H is positive
energy profile diagram
the energy changes that occur during the course of a reaction
enthalpy
heat content.
The sum of the chemical (potential) and kinetic energies in a substance;
Symbol = H
enthalpy change ^H
the difference in the total enthalpy of the products and the total energy of the reactants;
Symbol = ^H.
Also known as heat of reaction
exothermic
A reaction that releases (net ) energy into the surroundings.
^H is negative
heat of reaction
the exchange of heat between a system and its surroundings during a chemical reaction.
Under constant pressure
Symbol = ^H
law of conservation of energy
a scientific law that states energy cannot be created or destroyed.,
it can only be transformed from type to type.
e.g. chemical to light.
surroundings
The rest of the universe around a particular chemical reaction.
system
The chemical reaction
thermochemical equation
A chemical equation that includes the enthalpy change of the reaction as a reactant or a product.
