Chapter 14 Equilibrium Test Flashcards
The equilibrium constant is?
Concentration of products/concentration of reactants at equilibrium
What can Ksp be applied to?
Slightly soluble solutions
Which of the following would cause equilibrium to shift right?
Decrease in products
The common ion effect is used to explain what?
The shift in equilibrium position due to the concentration of an ion
Any change in temperature, concentration, or pressure on a system at equilibrium is called?
Stress
Which change would shift the equilibrium to the right?
Increase in pressure in an exothermic reaction
Reactions tend to run to completion if?
A gaseous product escapes or a precipitate forms
Which of the following can change an equilibrium constant?
Temperature
What must a ligand have?
A lone pair of electrons
A ligand is a molecule or ion that can?
Make a bond with a transition metal ion
What does concentration have to be at equilibrium?
The concentration of reactant and products must be constant
What does a large equilibrium constant mean?
Reaction is favoring the products (Keq > 1)
The smaller the value of the solubility product constant, the ______.
The lower the solubility of the compound
What happens at equilibrium?
Both the forward reaction and backward reaction have the same rate
What happens to reactants in completion reactions?
Almost all of the reactant reacts to form a product
What happens in a reverse reaction?
Products can reform reactants
What is chemical equilibrium?
Occurs when the forward and reverse reactions reach a state of balance in which the concentrations of the reactants and products remain the same, even though individual atoms may be changing
What is rate?
The speed at which a process occurs
Why is chemical equilibrium considered to be dynamic?
The rate of the forward reaction occurs at the same rate of the reversed reaction
Do atoms changing from products to reactants affect the concentration?
No, atoms can make that change but the overall concentration remains constant
What is a complex ion?
Any metal atom or ion that is bonded to more than 1 atom or molecule
What are ligands?
Molecules or anions that readily bond to metal ions with a lone pair of electrons
What is true about complex ions?
Complex ions formed from transition metals are often deeply colored
What is the solubility product of the salt in water?
The maximum concentration of salt in an aqueous solution
What does the solubility product measure?
A large class of salts that are said to be slightly soluble in water, which means that the ions in solution and any solid salt are at equilibrium
When do reversible reactions reach equilibrium?
When the concentration of the reactants and the products is constant
What is the law of chemical equilibrium?
At a given temperature, a chemical system might reach a state in which a particular ratio of reactant and product concentrations has a constant value.
If the law of chemical equilibrium is applied, what can be calculated?
The equilibrium constant (Keq)
What is the equilibrium constant?
Keq
What is Keq?
Keq is a constant which shows the ratio of product concentrations to reactant concentrations with each concentration raised to the power equal to its coefficient at equilibrium
What are some characteristics of Keq?
It is unit-less, constant at a certain temperature, can be found experimentally, is often reported in tables and can be looked up
What does it mean if Keq > 1?
Products are being favored at equilibrium
What does it mean if Keq < 1?
Reactants are favored at equilibrium
When writing an equilibrium expression, what is left out?
The concentration of any solid (s) or pure liquid (l) that takes part in the reaction is left out
For a reaction occurring in aqueous solution, water is ____?
Omitted, meaning you would not include H20 (l) when solving for equilbrium
Why are solids and pure liquids left out in the equilibrium expression?
They do not affect equilibrium because their concentrations stay constant throughout equilibrium
What does Keq show?
It shows if the reaction is favorable?
When are reactions favorable?
When reactions in which more products form than reactants are “favorable”
What is true about favorable reactions?
A favorable reaction will have a higher concentration of products than reactants, resulting in a large Keq at equilibrium
Describe the Keq value of 3.3 x 10^8
The reaction is very favorable because it has a large Keq value
Describe the Keq value of 4.5 x 10^-31
The reaction is not favorable because of its small Keq value
What does dissociation mean?
The breaking up of a compound into simpler constituents that are usually capable of recombining under other conditions
What are solubility product constants?
Equilibrium constants for the dissolution of slightly soluble salts
What is Ksp?
The product of the concentrations of the dissolved ions, multiplied each raised to the power of their coefficients in the balanced equation
What does solubility mean?
The solubility of a compound in water is the amount of the substance that will dissolve in a given volume of water at a given temperature
What does a small Ksp mean?
That very little of the compound will dissolve in water
What does a large Ksp mean?
That more of the compound will dissolve in water
What are most Ksp values for?
Sparingly/somewhat soluble compounds
Which of these is the least soluble? Why?
A: 8.4 x 10 ^-12
B: 1.1 x 10^ -49
C: 7.1 x 10^ 5
B is the least soluble because it has a small Ksp due to the high negative exponent
Which of these is the most soluble? Why?
A: 8.4 x 10 ^-12
B: 1.1 x 10^ -49
C: 7.1 x 10^ 5
C is the most soluble because it has a great Ksp due to its exponent being positive
Solubility product is only for _____?
Salts that have low solubility because soluble salts do not have Ksp values
How are chemical equations written when finding Ksp?
The solid salt is the reactant and the dissociated ions are the products
What is stress?
Another word for something causes a change in a system at equilibrium
Chemical equilbria respond to which three types of stress?
Changes in the concentrations of reactants or products, changes in temperature, and changes in pressure
What happens when stress is first applied to a system?
Equilibrium is disrupted and the forward and backward reactions are no longer equal
What is Le Chatelier’s Principle?
A principle that states that when a system at equilibrium is disrupted, the system adjusts in a way to reduce the change
