Author Wesley Tung Technical Things A chemical equation of a reaction uses mole ratios to describe the production of products from reactants In hydrogen and oxygen are reactants and water is a product ID: 463101
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Slide1
Chemical Equilibrium
Author: Wesley TungSlide2
Technical Things
A chemical equation of a reaction uses mole ratios to describe the production of products from reactants.
In
, hydrogen and oxygen are reactants, and water is a product.This equation has a 2:1:1 mole ratio.1 mole contains molecules/atoms.This is also known as Avogadro's number.
Slide3
Intro to Equilibrium
History
In 1803, Claude Louis Berthelot, a Savoyard-French chemist, discovered some chemical reactions were reversible.
Definition of EquilibriumThe state in a chemical reaction in which both products and reactants are present in concentrations that have no further tendency to change over time.Two types of chemical equilibrium exist:Static EquilibriumThe reaction is irreversible.Dynamic EquilibriumThe reaction is reversible.Slide4
Reaction Quotient
The reaction quotient is a constant that tell us the ratio of products to reactants at a specific state in the reaction.
For a reaction
, the reaction quotient is calculated by:
Brackets stand for concentration in molarity.
Molarity (M) =
Only
gaseous
and aqueous compounds are included in the equation.
Slide5
Equilibrium Constant
The equilibrium constant is the reaction quotient value for a system when it is in it’s equilibrium state.
Every system of equilibrium has a unique equilibrium constant (K) that is determined experimentally initially.
To do this, you must let the reaction run to its equilibrium state, then figure out the concentrations of each component. This constant allows us to determine whether the same system under different conditions is at equilibrium.When the system is at equilibrium.When , the system is not at equilibrium and will produce more products or reactants to achieve equilibrium. Slide6
Le Chatelier's Principle
History
Developed by Henry-Louis Le
Chatelier in 1884 to predict the change in disturbed equilibrium systems to re-achieve equilibrium. In general:Increasing the concentration of reactants causes more products to be made (Shift right).Increasing the concentration of products causes more reactants to be made (Shift left).Decreasing the volume but keeping everything else constant would shift the reaction towards the side of the reaction that produces the least total amount of moles.Increasing the volume but keeping everything constant would shift the reaction towards the side of the reaction that produces the most amount of moles.Slide7
Le Chatelier’s Principle
Temperature is unique
It doesn’t modify the reactant quotient like volume and concentration but modifies the
equilibrium constant.The shift depends on whether the reaction is exothermic or endothermic:Endothermic: Heat is a reactant and the reaction shifts right if you increase the temperature.Exothermic: Heat is a product and the reaction shifts left if you increase the temperature.