CH 112 Chapter 16: Chemical Equilibrium

What is static?

The reaction proceeds to completion

What is dynamic?

The forward and reverse reaction rates are equal

What are characteristics of a dynamic reaction

Some of each reactant and product must remain (no 0.0M)

No net change in concentration

What is homogeneous?

All reactants and products are in the same state

What is heterogeneous?

At least one reactant or product is in a different state

What is Kc derived from?

Only from substances that change in concentration: aqueous and gas.

What does aqueous vary with?

moles

What does gas vary with?

volume

What is the constant ratio of solids and liquids?

moles to volume

What Kp derived from

only gases

What is the equilibrium constant concentration of Kc?

\[products\] to \[reactants\] at a given temperature

What is the equilibrium constant pressure of Kp?

equilibrium pressure (in atm) of products to reactants at a given temperature.

What is the relationship equation between Kp and Kc?

Kp = Kc (RT)^dn

What is Kc > 10^3?

The reaction favors the products, and the reaction proceeds towards completion

What is Kc < 10^-3?

The reaction favors the reactants, and very little reaction occurs

what is 10^-3 < Kc < 10^3?

Significant concentrations of reactants and products remain: the reaction noticeably shifts when stressed.

What does the __reaction quotient__ relates to?

to non-equilibrium concentrations

What shows the reaction direction?

the relationship from Kc to Qc

What is Kc > Qc?

\[product\] increases as the reaction proceeds to equilibrium

What is Kc < Qc?

\[reactant\] increases as the reaction proceeds to equilibrium.

What is Kc = Qc?

The reaction is at equilibrium.

How do you know you need an ICE table?

The problem has to reference both initial equilibrium values and non-equilibrium values.

What is the Le Chatelier principle?

When a reaction at equilibrium is stressed, the reaction shifts to relieve the stress.

How is the reaction shift exhibited?

by a change in \[reactant\] and \[product\]

Left shift equals?

the \[reactant\] increasing

Right shift equals?

the \[products\] increasing

Where does reactions shift to?

they shift away from addition and toward removal.

What is another way reactions may shift?

By substituting non-equilibrium values into the Qc equation

What is not a type of stress?

Changing the amount of solid and liquid (unless adding H2O in aqueous solutions)

What only affects gases?

Pressure changes

What does changing the volume affect?

the partial pressure and molarity

What is volume inversely related to?

Partial Pressure

What happens when the volume increases?

The reaction shifts to more moles

What happens if the volume decreases?

The reaction shifts to fewer moles

What does changing the temperature apply to?

A completed reaction

What if dH > 0

Heat is a reactant

What if dH < 0

Heat is a product.

What happens when heat increases?

The reaction shifts to relieve the heat.

What happens when the heat decreases?

The reaction shifts to replace the heat.

What happens if a catalyst is added to a chemical equilibrium?

It does not affect any concentration

What happens to the activation energy when adding a catalyst to a chemical equilibrium?

The energy is lowered for both the forward and reverse reactions.

What happens to reaction rates when adding a catalyst to a chemical equilibrium?

It increases for both the forward and reverse reactions (increase by the same amount)