Topic 1 : Video B: Law of Mass Action
● You cannot find the K value of a solid or a liquid. But you can find the K value of a gas or
a solution.
● K is a ratio of activities with the products are in the numerator and the reactants are in
the denominator and to the power of the reaction stoichiometry. It is the equilibrium
constant/position.
● For a given reaction at constant temperature, K is constant.
○ K only changes when temperatures changes
Topic 1: Video C: The Equilibrium Constant (K)
● K is the measure of how far a reaction will proceed in the direction it has be written
○ By convention, if K is the order of 10^8 we say that the reaction goes to
completion.
● K can be any POSITIVE NUMBERS.
● When K>1: product favored reaction. The reaction proceeds forwards. At equilibrium,
there will be a lot of product and very little reactant. Therefore, large K value, the
reaction is towards the product side (right) and runs to completion.
● When K<1: reaction favored reaction. The reaction does not effectively happen. At
equilibrium, there is a lot of reactant and very little product. Therefore, small K value , the
reaction is towards the reactants side (left) and it does not effectively happen.
Topic 1: Video D: Equilibrium Expressions of the Same Chemical Reactions
● Synthesis Reaction: less K value; Decomposition Reaction: more K value
This inverse relationship: K2= (1 / K1)
● When you multiply a reaction by a factor of N. K is raised to the power N. Knew = KN.
● When you add the reactions together for the new K, make sure to cross multiply and get
rid of similar compounds or elements. Then form the new chemical reaction. The new K
value will be the products of the K values of the reactions being added.
Knew= K1 x K2
Topic 2: Video A: Introducing Q
● When K is neither large or very small, we must consider the reaction conditions to
predict the direction in which it moves in order to reach equilibrium.
● Non-equilibrium: Reaction Quotient (Q): solution concentration at any arbitrary set of
conditions. While Reaction Quotient (K) is the solution concentrations ONLY at
equilibrium.
● Q = (products at non-equilibrium) / (reactants at non-equilibrium)
We will compare the values of Q and K to predict the direction of a reaction.
● If Q<K : reaction proceeds forward (right) to compensate for the significant amount of
reactant, and create more product to create an equal amount of product and reactant.
● If Q>K: reaction proceeds backwards (left) to compensate for the significant amount of
product, and decompose to make more reactants to create an equal amount of products
and reactants.
● If Q=K: reaction is at equilibrium
1
,Topic 2: Video B: Le Chatelier’s Principle:
● It does not matter how we start a reaction, it will always proceed to equilibrium. The
reactant particles are equal to the product particles.
● When a system at equilibrium is changed, the system responds back by shifting back to
equilibrium.
● Once the equilibrium has been re-established, the equilibrium position has changed,
even though the ratio of concentrations are the same again.
● There are four types of stress
○ change in concentrations
○ change in temperature
○ change in volume/pressure
○ addition of inert gas or adding a catalyst
Topic 2: Video C: Changes in concentrations:
● Increasing concentration:
If we add more reactant to the system, there is now more reactant than there was at equilibrium
(Q<K). The equilibrium will shift to the right, towards the products, to consume the extra reactant
and until Q=K.
If we add more product to the system, there is now more product than there was at equilibrium
(Q>K). The equilibrium will shift to the left, towards the reactant, to consume the extra product
until Q=K.
● Decreasing concentration:
If we remove reactant from the system, there is now less reactant in the system than there was
at equilibrium, the equilibrium will shift towards the right, to make more reactants.
If we remove products from the system, there is now less product in the system than there way
at equilibrium, the equilibrium will shift towards left, to make more product.
Topic 2: Video D: Changes in Temperature
● Exothermic: release heat and heat can be thought of as product in an exothermic
reaction.
Increase heat as a product, the reaction will shift towards the reactant to consume the heat.
Decrease heat as a product, the reaction will shift towards the product to produce more heat.
● Endothermic: reaction absorbs heat and heat can be thought of as a reactant in an
endothermic reaction.
Increase heat as a reactant, the reaction will shift towards the product.
Decrease the heat as a reactant, the reaction will shift towards the reactant.
● When temperature changes, the equilibrium position shifts and the numerical
value of K is changed.
● When the reaction moves to the right → there is more product than the reactant,
making the K value is big.
2
, ● When the reaction moves to the left ← there is less product than the reactant,
making the K value small.
Topic 2: Video E: Changes in Volume/Pressure
● The partial pressure of a gas is the pressure exerted on the wall by only the gaseous
species.
● Dalton’s Law of Partial Pressure: In a system with multiple gaseous species, the total
pressure exerted on the wall of the container is the sum of the pressures that each gas
would exert if it were alone.
● For this mixture of gases in a closed container: Ptotal= P1+P2+P3
● If we stress the system by changing the volume, we will be also changing the pressure.
If you increase the volume, you decrease the pressure. If you decrease the volume, you
increase the pressure.
● To compensate for the change in volume/pressure, the system responds by changing the
pressure by changing the number of moles.
● The equilibrium shift depends on the moles and the balanced equation.
● If we increase the volume: pressure decreases and there is a shift towards the side with
more moles of gas.
● If we decrease the volume: pressure increases and there is a shift towards the side with
less moles of gas.
● When the changes occur in volume, but the moles of the gas are the same for the
reactant and the product, there is no shift in equilibrium.
Topic 2: Video F: Addition of a noble gas or a catalyst
● Adding a noble gas changes the overall pressure, but causes no shift in equilibrium or K
value because it does not affect the concentration or partial pressure.
● Addition of a catalyst speeds up the rate of a reaction but the equilibrium remains
unchanged and the numerical value of K remains unchanged.
Topic 3: Video A: Introduction to Acids and Bases
● Arrhenius Theory: Strong Acids and Base
Acids produce H3O when dissolved in water. Base produce OH when dissolved in water.
● Bronsted-Lowry: Weak Acids and Bases
Do not dissociate completely and are equilibrium reactions.
● All acids and bases have conjugate acids and bases pairs.
Topic 3: Video B: Water is Amphoteric
● An acid will always donate a proton to the base it is reacting with to generate its
conjugate base.
● A base will always accept a proton to the acid it is reacting with to generate its conjugate
acid.
● Water acts as a base around acid. While around base, water acts as an acid. It is an
amphoteric species that can act as either an acid or base.
Topic 4: Video C: Strengths of Acids and Bases
3
, ● We can use the equilibrium constant (K) to determine the relative strengths of acids and
bases.
● Acid dissociation determines the strength:
○ Strong acids dissociate completely in water and have large Ka values.
The equilibrium position lies far to the right.
Conjugate base is weaker than water.
Ka ﹥ 1 then [H3O] ﹥[HA]
● Weak acids do not dissociate completely in water and have small Ka values. The
equilibrium position lies far to the left.
Conjugate base is stronger than water.
Ka ﹤1 then [H3O] ﹤[HA]
● Single arrow for strong acid reaction and double arrows for weak acid reaction.
● A weak acid with a larger Ka dissociates and produces a greater concentration of
protons.
Stronger weak acid → more dissociation → larger proton concentration → larger Ka value
● Weak bases are Bronsted-Lowry bases.
● Strong bases are Arrhenius bases that also contain a hydroxide.
Strong Acids Strong Bases
Hydrochloric Acid (HCl) Sodium Hydroxide (NaOH)
Hydrobromic Acid (HBr) Potassium Hydroxide (KOH)
Nitric Acid (HNO3) Lithium Hydroxide (LiOH)
Perchloric Acid (HClO4) Strontium Hydroxide (Sr(OH)2)
Sulfuric Acid (H2SO4) Calcium Hydroxide (Ca(OH)2)
Chloric Acid (HClO3) Barium Hydroxide (Ba(OH)2)
(only the first proton) Group 1 and few Group 2 metal hydroxides
Topic 4: Video D: What is pH?
● How acidic or basic a solution is?
● Depends on the concentration of protons (H+) in the solution.
● The pH value of a solution is calculated based on the concentration of hydronium ion
[H3O].
● A log 10 based scale is used to represent the acidity of a solution using numbers.
Bases: pH ﹥ 7 Neutral: pH = 7 Acids: pH ﹤ 7
4
● You cannot find the K value of a solid or a liquid. But you can find the K value of a gas or
a solution.
● K is a ratio of activities with the products are in the numerator and the reactants are in
the denominator and to the power of the reaction stoichiometry. It is the equilibrium
constant/position.
● For a given reaction at constant temperature, K is constant.
○ K only changes when temperatures changes
Topic 1: Video C: The Equilibrium Constant (K)
● K is the measure of how far a reaction will proceed in the direction it has be written
○ By convention, if K is the order of 10^8 we say that the reaction goes to
completion.
● K can be any POSITIVE NUMBERS.
● When K>1: product favored reaction. The reaction proceeds forwards. At equilibrium,
there will be a lot of product and very little reactant. Therefore, large K value, the
reaction is towards the product side (right) and runs to completion.
● When K<1: reaction favored reaction. The reaction does not effectively happen. At
equilibrium, there is a lot of reactant and very little product. Therefore, small K value , the
reaction is towards the reactants side (left) and it does not effectively happen.
Topic 1: Video D: Equilibrium Expressions of the Same Chemical Reactions
● Synthesis Reaction: less K value; Decomposition Reaction: more K value
This inverse relationship: K2= (1 / K1)
● When you multiply a reaction by a factor of N. K is raised to the power N. Knew = KN.
● When you add the reactions together for the new K, make sure to cross multiply and get
rid of similar compounds or elements. Then form the new chemical reaction. The new K
value will be the products of the K values of the reactions being added.
Knew= K1 x K2
Topic 2: Video A: Introducing Q
● When K is neither large or very small, we must consider the reaction conditions to
predict the direction in which it moves in order to reach equilibrium.
● Non-equilibrium: Reaction Quotient (Q): solution concentration at any arbitrary set of
conditions. While Reaction Quotient (K) is the solution concentrations ONLY at
equilibrium.
● Q = (products at non-equilibrium) / (reactants at non-equilibrium)
We will compare the values of Q and K to predict the direction of a reaction.
● If Q<K : reaction proceeds forward (right) to compensate for the significant amount of
reactant, and create more product to create an equal amount of product and reactant.
● If Q>K: reaction proceeds backwards (left) to compensate for the significant amount of
product, and decompose to make more reactants to create an equal amount of products
and reactants.
● If Q=K: reaction is at equilibrium
1
,Topic 2: Video B: Le Chatelier’s Principle:
● It does not matter how we start a reaction, it will always proceed to equilibrium. The
reactant particles are equal to the product particles.
● When a system at equilibrium is changed, the system responds back by shifting back to
equilibrium.
● Once the equilibrium has been re-established, the equilibrium position has changed,
even though the ratio of concentrations are the same again.
● There are four types of stress
○ change in concentrations
○ change in temperature
○ change in volume/pressure
○ addition of inert gas or adding a catalyst
Topic 2: Video C: Changes in concentrations:
● Increasing concentration:
If we add more reactant to the system, there is now more reactant than there was at equilibrium
(Q<K). The equilibrium will shift to the right, towards the products, to consume the extra reactant
and until Q=K.
If we add more product to the system, there is now more product than there was at equilibrium
(Q>K). The equilibrium will shift to the left, towards the reactant, to consume the extra product
until Q=K.
● Decreasing concentration:
If we remove reactant from the system, there is now less reactant in the system than there was
at equilibrium, the equilibrium will shift towards the right, to make more reactants.
If we remove products from the system, there is now less product in the system than there way
at equilibrium, the equilibrium will shift towards left, to make more product.
Topic 2: Video D: Changes in Temperature
● Exothermic: release heat and heat can be thought of as product in an exothermic
reaction.
Increase heat as a product, the reaction will shift towards the reactant to consume the heat.
Decrease heat as a product, the reaction will shift towards the product to produce more heat.
● Endothermic: reaction absorbs heat and heat can be thought of as a reactant in an
endothermic reaction.
Increase heat as a reactant, the reaction will shift towards the product.
Decrease the heat as a reactant, the reaction will shift towards the reactant.
● When temperature changes, the equilibrium position shifts and the numerical
value of K is changed.
● When the reaction moves to the right → there is more product than the reactant,
making the K value is big.
2
, ● When the reaction moves to the left ← there is less product than the reactant,
making the K value small.
Topic 2: Video E: Changes in Volume/Pressure
● The partial pressure of a gas is the pressure exerted on the wall by only the gaseous
species.
● Dalton’s Law of Partial Pressure: In a system with multiple gaseous species, the total
pressure exerted on the wall of the container is the sum of the pressures that each gas
would exert if it were alone.
● For this mixture of gases in a closed container: Ptotal= P1+P2+P3
● If we stress the system by changing the volume, we will be also changing the pressure.
If you increase the volume, you decrease the pressure. If you decrease the volume, you
increase the pressure.
● To compensate for the change in volume/pressure, the system responds by changing the
pressure by changing the number of moles.
● The equilibrium shift depends on the moles and the balanced equation.
● If we increase the volume: pressure decreases and there is a shift towards the side with
more moles of gas.
● If we decrease the volume: pressure increases and there is a shift towards the side with
less moles of gas.
● When the changes occur in volume, but the moles of the gas are the same for the
reactant and the product, there is no shift in equilibrium.
Topic 2: Video F: Addition of a noble gas or a catalyst
● Adding a noble gas changes the overall pressure, but causes no shift in equilibrium or K
value because it does not affect the concentration or partial pressure.
● Addition of a catalyst speeds up the rate of a reaction but the equilibrium remains
unchanged and the numerical value of K remains unchanged.
Topic 3: Video A: Introduction to Acids and Bases
● Arrhenius Theory: Strong Acids and Base
Acids produce H3O when dissolved in water. Base produce OH when dissolved in water.
● Bronsted-Lowry: Weak Acids and Bases
Do not dissociate completely and are equilibrium reactions.
● All acids and bases have conjugate acids and bases pairs.
Topic 3: Video B: Water is Amphoteric
● An acid will always donate a proton to the base it is reacting with to generate its
conjugate base.
● A base will always accept a proton to the acid it is reacting with to generate its conjugate
acid.
● Water acts as a base around acid. While around base, water acts as an acid. It is an
amphoteric species that can act as either an acid or base.
Topic 4: Video C: Strengths of Acids and Bases
3
, ● We can use the equilibrium constant (K) to determine the relative strengths of acids and
bases.
● Acid dissociation determines the strength:
○ Strong acids dissociate completely in water and have large Ka values.
The equilibrium position lies far to the right.
Conjugate base is weaker than water.
Ka ﹥ 1 then [H3O] ﹥[HA]
● Weak acids do not dissociate completely in water and have small Ka values. The
equilibrium position lies far to the left.
Conjugate base is stronger than water.
Ka ﹤1 then [H3O] ﹤[HA]
● Single arrow for strong acid reaction and double arrows for weak acid reaction.
● A weak acid with a larger Ka dissociates and produces a greater concentration of
protons.
Stronger weak acid → more dissociation → larger proton concentration → larger Ka value
● Weak bases are Bronsted-Lowry bases.
● Strong bases are Arrhenius bases that also contain a hydroxide.
Strong Acids Strong Bases
Hydrochloric Acid (HCl) Sodium Hydroxide (NaOH)
Hydrobromic Acid (HBr) Potassium Hydroxide (KOH)
Nitric Acid (HNO3) Lithium Hydroxide (LiOH)
Perchloric Acid (HClO4) Strontium Hydroxide (Sr(OH)2)
Sulfuric Acid (H2SO4) Calcium Hydroxide (Ca(OH)2)
Chloric Acid (HClO3) Barium Hydroxide (Ba(OH)2)
(only the first proton) Group 1 and few Group 2 metal hydroxides
Topic 4: Video D: What is pH?
● How acidic or basic a solution is?
● Depends on the concentration of protons (H+) in the solution.
● The pH value of a solution is calculated based on the concentration of hydronium ion
[H3O].
● A log 10 based scale is used to represent the acidity of a solution using numbers.
Bases: pH ﹥ 7 Neutral: pH = 7 Acids: pH ﹤ 7
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