Youngless Chapter 17 - Chemical Equilibrium

completion

When a chemical reaction occurs and there is a complete conversion of reactants to product, the reaction goes to ____.

reversible

Some chemical reactions do not go to completion but they appear to stop or be completed. They are _____.

Reversible reaction

A ____ is a chemical reaction in which the products can regenerate the original reactants.

forward; reverse

The reaction can move in the ___ or ____ direction.

Chemical equilibrium

____ is reached when the rate of the forward reaction is equal to the rate of the reverse reaction.

constant

The concentration of the reactants and products become _____. (NOT equal)

stopped

Remember that reaching equilibrium does not mean the reaction has ____!

Law of Chemical Equilibrium (Mass Action)

___ states that the relative concentration of reactants and products at equilibrium can be expressed in terms of an equilibrium constant. (Keq)

Equilibrium constant

____ is the numerical value of the ratio of product concentrations to reactant concentrations, with each concentration raised to the power equal to its coefficient in the balanced equation.

Keq

The generic symbol for the equilibrium constant is __.

temperature

The value of Keq is constant only at a specified ____.

right (More products than reactants)

If K>1, then the equilibrium will lie to the ___.

left (More reactants than products)

If K<1, then the equilibrium will lie to the ___.

homogeneous equilibrium

___ is when the reactant and products are in the same physical state.

heterogeneous equilibrium

A ____ is when the substances in a chemical reaction are different states.

solid; liquid

Concentration of a pure ___ or ___ is constant, and NOT included in the equilibrium expression

Concentrations of reactants and products, Pressure, Temperature

Chemical equilibrium can be disturbed (stressed) and shifted away from equilibrium by: ___, ___, ___

Le Chatelier's Principle

____ states:If an external stress is applied to a system at equilibrium, the system adjusts in such a way that the stress is partially offset as the system reaches a new equilibrium position.

left (AWAY from the products)

If you increase concentration of product(s), the equilibrium will shift to the __.

right (TOWARD the products)

If you decrease concentration of product(s), the equilibrium will shift to the __.

right (TOWARD reactants)

If you increase the concentration of the reactants, the equilibrium will shift to the __.

left (AWAY reactants)

If you decrease the concentration of the reactants, the equilibrium will shift to the __.

fewest

CHANGE: increase pressure

SHIFT IN THE EQUILIBRIUM: side with the ___ moles of gas

most

CHANGE: decrease pressure

SHIFT IN THE EQUILIBRIUM: side with the ___ moles of gas

most

CHANGE: increase volume

SHIFT IN THE EQUILIBRIUM: side with the ___ moles of gas

fewest

CHANGE: decrease volume

SHIFT IN THE EQUILIBRIUM: side with the ___ moles of gas

equilibrium constant and equilibrium of the reaction

Temperature change causes a change in _____ AND ______.

AWAY from the heat (absorbs heat)

When the temperature is increased the equilibrium will shift ___.

1. Reaction must be reversible

2. The 2 reversible reactions must be at the same rate

3. The concentration of reactants and products must be CONSTANT, not equal to each other

What are the 3 Requirements for Equilibrium?

Concentration of Reactants Decreases

Concentration of Products Increases

What happens to the reactant and product concentrations if you SHIFT TO THE RIGHT?

Concentration of Reactants Increases

Concentration of Products Decreases

What happens to the reactant and product concentrations if you SHIFT TO THE LEFT?

TOWARDS the heat (release the heat)

When the temperature is decreased the equilibrium will shift ___.

Increases

If a reaction shifts to the RIGHT because of a temperature change, the Keq will ______.

Decreases

If a reaction shifts to the LEFT because of a temperature change, the Keq will ______.

No Shift, a catalyst is not a stress

What direction will the reaction shift if a catalyst is added?