Module #15: Chemical Equilibrium Flashcards
What is the Equilibrium Constant equation?
K = [C]^c eq [D]^d eq / [A]^a eq [B]^b eq
Define Chemical Equilibrium
The point at which both the forward and reverse reactions in a chemical equation have equal reaction rates: When this occurs, the amounts of each substance in the chemical reaction will not change, despite the fact that Both reactions still proceed.
How do you read the equilibrium constant?
When K is large, the equilibrium is weighted towards the products.
When K is small, the equilibrium is weighted toward the reactants.
When K is near unity, the equilibrium is balanced between reactants and products.
What do you include in the Equilibrium Constant equation?
Include gas and aqueous substances.
Ignore: Solids and liquids.
What is Le Chateleir’s principle?
When a stress (such as a change in concentration, pressure, or temperature) is applied to an equilibrium, the reaction will shift in a way that relieves the stress and restores equilibrium.
What substance states does Le Chateleir’s Principle apply to?
Le Chateleir’s principle ignores solids (s) and liquids (l) as a source of stress to the equilibrium, however, it *does acknowledge substances in the aqueous phase (aq) and the gaseous phase (g).
How does Le Chateleir’s Principle work according to pressure?
[+] When an equilibrium is subjected to an increase in pressure, it will shift away from the side with the largest number of gas molecules.
[-] If pressure decreases, the equilibrium will shift toward the side with the largest number of gas molecules.
[0] Finally, if there are no gases in the equation or if the number of gas molecules is the same on both sides, nothing will happen.
How does Le Chateleir’s Principle work according to temperature?
[+] When the temperature is raised, an equilibrium will shift away from the side of the equation that contains energy.
[-] When the temperature is lowered, the reaction will shift toward the side that contains energy.
How do we rate an acid according to its Ionization Constant?
[+] If the ionization constant of an acid is large the acid is considered a strong acid.
[-] If the ionization constant is not large, we call it a weak acid.
In general, the larger the ionization constant, the stronger the acid.
Define pH scale.
(pH – potential Hydrogen) A scale used to determine the concentration of H+ in an aqueous solution. It spans from 1 to 10, 0 to 6.9 being acidic and 7.1 to 14 considered basic.
How are acids rated on the pH scale?
Solutions with pH 0 - 1.9 are considered strongly acidic and solutions with pH 2 - 6.9 are weakly acidic.
How are bases rated on the pH scale?
Solutions with pH 7.1 - 12 are weakly basic and solutions with pH 12.1 - 14 are strongly basic.
What is 7 considered on the pH scale?
Solutions with a pH of 7 are considered to be neutral – neither acidic nor basic.
Define Acid Ionization Reaction.
The reaction in which an H+ separates from an acid molecule so that it can be donated in another reaction.
Define Acid Ionization Constant.
The equilibrium constant for an acid’s ionization reaction. (Ka). The higher the number, the stronger the acid.
