Chemistry Chapter 17 - Chemical Equilibrium

Haber-Bosch Process

a method of directly synthesizing ammonia from hydrogen and nitrogen, which made the manufacture of ammonia economically feasible

Ethics of Haber Process

• used to form explosives in WWI

• used to form hydrogen cyanide, which was used in gas chambers during WWII

• Harm to nitrogen cycle

• Fertilizer run-off

Chemical Equilibrium

results when the forward and reverse reactions proceed at the same rate

Reversible Reactions

a reaction that can occur in both the forward and the reverse directions (Haber process)

What does chemical equilibrium refer to?

balanced changes or the concentration of each stable is stable

Most natural processes are…

reversible reactions

Characteristics of Reversible Reactions

both reactants and products exist together as a mixture; the ratio in which reactants and products are present in the reaction depends on the relative speeds of the forward and reverse reactions; changing the rate of either the forward or reverse reactions changes the ratio of products and reactants

Irreversible Reactions

reactions in which the reactants convert to products but the products cannot convert back into the reactants

Dynamic Equilibrium

the particles involved in a reaction are in constant motion even after equilibrium is achieved

What happens to the ratio between the reactants and the products in dynamic equilibrium?

it remains unchanged

What do we use to display equilibrium?

a half arrow going two ways

Physical Changes in Equilibrium

water evaporation and water dissolving

Reaching Equilibrium

the forward and reverse reactions will be equal; the concentration of the reactants and products will be constant

Equilibrium Position

the concentrations of the substances at equilibrium and is dependent on the conditions at equilibrium

Equilibrium State

rate is the same; concentrations are constant

Equilibrium Constant Equation

aA + bB —> cC + dD —→ K_eq = [C]^c [D]^d/ [A]^a [B]^b

Constant Values for Equilibrium Constant Equation

k_eq > 1 - forward reactants predominates ([products] > [reactants])

Keq < 1 - reverse reaction predominates ([reactants] > [products])

Law of Chemical Equilibrium

at a specific temperature, a chemical system may reach a point at which the ratio of the concentration of the products to the reactants is constant

Equilibrium Constant

a numerical expression of the ratio of the product equilibrium concentrations to the reactant equilibrium concentrations

In an equilibrium expression, the concentrations of…do not change and must be crossed out

solids and liquids