Every reaction proceeds until an equilibrium point is reached. Depending on other conditions, this may be reached rapidly or slowly, but it can be influenced.
Chemical equilibrium is always a dynamic equilibrium, with changes in one reaction direction being influenced by changes the other way restoring the status quo.
The study of chemical equilibrium is an important part of chemistry because most chemical reactions proceed only to equilibrium and halt after that is reached.
The equilibrium point often changes with physical conditions such as the operating temperature, pressure, and the concentrations of reactants.
The speed of a reaction to equilibrium changes with physical conditions such as temperature, pressure, and the surface areas and concentrations of reactants.
Chemical changes occur at different speeds, which can be affected by the presence of a catalyst, which affects the rate of reaction, but is not changed.
A catalyst is something which influences the rate at which a chemical reaction proceeds to equilibrium, but which is not itself changed by the reaction.
A catalyst can be used to increase the speed at which an equilibrium is reached, but the catalyst does not influence the actual equilibrium point in any way.
Enzymes operate as catalysts best under very specific conditions of temperature and acidity, and they can all be destroyed by high temperatures.
Enzymes are found in all living things: they are proteins, catalysts that are coded for by individual genes. They control all biochemical pathways in the cell.
An enzyme is a protein which operates in a biochemical reaction in the same way as a catalyst in a chemical reaction, and like a catalyst, remains unchanged.
Every chemical reaction is associated with an equilibrium constant, which may be predicted with reasonable accuracy, using standard known values.
In 1803, Claude Berthollet stated that the proportions of the reactants affects the direction in which chemical reactions take place, changing the equilibrium.
The speed of a reaction varies with the surface area of the reactants, as this increases the frequency of particle contact, increasing the chances for reaction.
The reaction of an equilibrium to changes in physical conditions is described by Le Chatelier's principle: the equilibrium moves to accommodate the changes.
The equilibrium point of a chemical reaction may be influenced by changing the physical factors like heat and pressure to favour one reaction over another.
In 1876, Josiah Gibbs began writing on phase equilibria, the free energy as the driving force behind chemical reactions, and chemical thermodynamics in general.
Some chemical reactions only take place if the energy barrier is overcome by heat or a catalyst: once started the reaction provides the energy to keep it going.