Chapter 15 reading notes

Seite 1

15.1 The Concept of Equilibrium

equilibrium state: a mixture of reactants and products whose concentrations no longer change with time

shown by double arrows in opposite directions <-->

forward reaction and the reverse reaction are elementary reactions

amount of reactants = the amount of products made

For equalibrium to occur,neither reactants nor products can escape from the system

equilibrium constant: is the rate constant ratio of the reactant and product constant

-@constant equilibrium, at a constant temperature, the ratio equals a specific value

once equilibrium is established, the concentrations of reactants and products no longer change

dynamic equilibrium: when products and reactants are continuously converting back and forth

15.2 The Equilibrium Constant

Haber process: is critical for the production of fertilizers and therefore critical to the world's food supply

The equilibrium condition is reached from either direction

law of mass action: for any reaction, the relationship between the concentrations of the reactants and products present at equilibrium

aA + bB <----> dD + eE

To find the rate K(c)= [D] (little d on top) [E] (little e on top]/[A] (little a on top] [B] (little b on top)

products / reactants

this relationship is the equilibrium-constant expression

expression depends only on the stoichiometry of the reaction, not on its mechanism

- it does not depend on the initial amounts of reactants and products

- it does not matter whether other substances are present, as long as they do not react with a reactant or product

K(constant)- depends only on the particular reaction and on the temperature

Evaluation K (constant)

pg. 634