Advanced Reaction Topics Advanced Reaction Topics l Reaction

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Advanced Reaction Topics

Advanced Reaction Topics

Advanced Reaction Topics l Reaction Rates l Redox Chemistry l Equilibrium l Acids and

Advanced Reaction Topics l Reaction Rates l Redox Chemistry l Equilibrium l Acids and Bases

Reaction Rates

Reaction Rates

Reaction Rates l Things that affect the rate of a reaction l Temperature l.

Reaction Rates l Things that affect the rate of a reaction l Temperature l. Increasing the temperature 10°C doubles the reaction rate (typically) l Concentration l Surface Area l Catalysts & Enzymes l Every reaction is different and has a different reaction rate.

Collision Theory Reactions happen when molecules collide with each other l The reaction only

Collision Theory Reactions happen when molecules collide with each other l The reaction only happens IF: l l They collide with enough energy l They collide with the right orientation.

How Do They Relate? l Things that affect the rate of a reaction l

How Do They Relate? l Things that affect the rate of a reaction l Temperature l. Increasing temperature increases the kinetic energy in a collision. l. Kinetic energy is the energy of motion of an object l. More collisions will have enough energy to have an effective collision

How Do They Relate? l Things that affect the rate of a reaction l

How Do They Relate? l Things that affect the rate of a reaction l Concentration l. Increases the number of particles in the same volume and therefore the number of collisions l Surface Area l. Increases the accessible area for collisions

How Do They Relate? l Things that affect the rate of a reaction l

How Do They Relate? l Things that affect the rate of a reaction l Catalysts and Enzymes l. Lower the amount of energy needed for a reaction to take place, so more effective collisions result

Redox Chemistry

Redox Chemistry

Electrolysis l Run a current through water. l Splits water into hydrogen and oxygen

Electrolysis l Run a current through water. l Splits water into hydrogen and oxygen l 2 H 2 O 2 H 2 + O 2

Oxidation Numbers l Describes the relative amount of electrons associated with a particular atom

Oxidation Numbers l Describes the relative amount of electrons associated with a particular atom l Has no actual physical meaning (for the most part) l Only an electron bookkeeping method.

Finding Oxidation Numbers 1. 2. Every uncombined element in its natural state has an

Finding Oxidation Numbers 1. 2. Every uncombined element in its natural state has an oxidation number of zero. The oxidation number of a monatomic ion is its charge.

Finding Oxidation Numbers 3. Remember the following: l l l 4. Fluorine in a

Finding Oxidation Numbers 3. Remember the following: l l l 4. Fluorine in a compound is always -1 Hydrogen is a +1 normally in a compound. It is -1 when a hydride. Oxygen is almost always -2 in a compound unless it is a peroxide (-1) The sum of the individual oxidation numbers on every atom in a species is equal to the overall charge on that species.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. CHF 3

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. Ba. Cl 2

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. KNO 3

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. S 2 O 32 -

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. P 4

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. (NH 4)2 C 2 O 4

Oxidation Numbers WB Practice Give the oxidation number of every element in the following

Oxidation Numbers WB Practice Give the oxidation number of every element in the following compounds. Ca. S Mg. F 2 HNO 3 H 2 O 2 Na 2 S 2 O 3

Vanadium Oxidation States l Vanadium oxidation states. mov

Vanadium Oxidation States l Vanadium oxidation states. mov

Uses of Redox Chemistry Batteries l Harnessed flow of electrons driven by redox reaction.

Uses of Redox Chemistry Batteries l Harnessed flow of electrons driven by redox reaction. Car battery

Alkaline Batteries

Alkaline Batteries

Electroplating

Electroplating

Corrosion

Corrosion

Equilibrium

Equilibrium

l Rules: l No Fishbowl Demo “goal-tending” l Get water in beaker, not around

l Rules: l No Fishbowl Demo “goal-tending” l Get water in beaker, not around it

l What Fishbowl Demo are the characteristics once it reaches equilibrium? l The amount

l What Fishbowl Demo are the characteristics once it reaches equilibrium? l The amount of “reactants” and “products” is not changing l “Reactions” are still occurring in both the forward and reverse direction. l The rate of the “reactions” is the same at equilibrium

Characteristics of Equilibrium l The amounts of the reactants and products do not change

Characteristics of Equilibrium l The amounts of the reactants and products do not change while the system is at equilibrium.

Characteristics of Equilibrium l Consider: N 2 + 3 H 2 ⇌ 2 NH

Characteristics of Equilibrium l Consider: N 2 + 3 H 2 ⇌ 2 NH 3 Notice the double half arrows

Characteristics of Equilibrium The forward and reverse reactions still both occur but at the

Characteristics of Equilibrium The forward and reverse reactions still both occur but at the same rate. l For this reason, equilibrium can also be called dynamic equilibrium l

Equilibrium Constants l We can calculate the equilibrium constant for a reaction at equilibrium

Equilibrium Constants l We can calculate the equilibrium constant for a reaction at equilibrium by measuring the concentrations of each species involved, then determining the ratio of products to reactants. Keq>1 means that the reaction favors the products l Keq<1 means that the reaction favors the reactants l

Equilibrium Constants l

Equilibrium Constants l

Practice Problem l

Practice Problem l

Practice Problem l

Practice Problem l

Making Changes to an Equilibrium System l How does changing the amount of one

Making Changes to an Equilibrium System l How does changing the amount of one species affect the equilibrium? l An equilibrium system must respond to changes. l A dynamic system must respond to any changes made.

Le Chatelier's Principle l “When a stress is placed on an equilibrium system, the

Le Chatelier's Principle l “When a stress is placed on an equilibrium system, the equilibrium will shift to relieve that stress. ” l The equilibrium may shift to the right l To make more Products l To reduce the amount of Reactants l The equilibrium may shift to the left l To make more Reactants l To reduce the amount of Products

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2 O)62+ + 4 Cl– (blue) (pink) exothermic What is the stress on the equilibrium if 12 M HCl is added? Which way does the equilibrium shift to relieve the stress? Why? What will it look like?

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2 O)62+ + 4 Cl– (blue) (pink) exothermic What is the stress on the equilibrium if H 2 O is added? Which way does the equilibrium shift to relieve the stress? Why? What will it look like?

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2 O)62+ + 4 Cl– (blue) (pink) exothermic What is the stress on the equilibrium if Ag+ is added? Which way does the equilibrium shift to relieve the stress? Why? What will it look like?

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2 O)62+ + 4 Cl– (blue) (pink) exothermic What is the stress on the equilibrium if heat is added? Which way does the equilibrium shift to relieve the stress? Why? What will it look like?

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2

Le Chatelier's Principle Co. Cl 42– + 6 H 2 O ⇌ Co(H 2 O)62+ + 4 Cl– (blue) (pink) exothermic What is the stress on the equilibrium if heat is removed (cooling)? Which way does the equilibrium shift to relieve the stress? Why? What will it look like?

Le Chatelier's Principle 2 NO 2(g) ⇌ N 2 O 4(g) brownish red colorless

Le Chatelier's Principle 2 NO 2(g) ⇌ N 2 O 4(g) brownish red colorless exothermic If we cool the gasses which way does the equilibrium shift? Why? What will it look like?

Le Chatelier's Principle 2 NO 2(g) ⇌ N 2 O 4(g) brownish red colorless

Le Chatelier's Principle 2 NO 2(g) ⇌ N 2 O 4(g) brownish red colorless exothermic If we warm the gasses which way does the equilibrium shift? Why? What will it look like?

Le Chatelier's Principle 2 NO 2(g) ⇌ N 2 O 4(g) brownish red colorless

Le Chatelier's Principle 2 NO 2(g) ⇌ N 2 O 4(g) brownish red colorless exothermic If we release pressure on the gasses which way does the equilibrium shift? Why? What will it look like?

Acids and Bases

Acids and Bases

Hydrochloric Acid l HCl(aq) l What type of compound is it? type of electrolyte

Hydrochloric Acid l HCl(aq) l What type of compound is it? type of electrolyte is hydrochloric acid?

Hydrochloric Acid l Why does it light up? l What l Is must be

Hydrochloric Acid l Why does it light up? l What l Is must be present in solution? hydrochloric acid an ionic compound? l No. It is in a small subset of covalent compounds.

Hydrochloric Acid l It must be making some ions in solution l What l

Hydrochloric Acid l It must be making some ions in solution l What l HCl are the ions? + H 2 O H 3 O+(aq) + Cl-(aq)

Hydrochloric Acid l H 3 O + is called the hydronium ion l Things

Hydrochloric Acid l H 3 O + is called the hydronium ion l Things that make hydronium ions in water are called acids.

A Word About Hydronium l Depending on how you look at it acids make

A Word About Hydronium l Depending on how you look at it acids make l H+ - hydrogen ion l H 3 O+ - hydronium ion l The two are interchangable l H + + H 2 O H 3 O + l Anytime you see one it can mean the other.

Common Acids Hydrochloric acid (HCl) l Muriatic acid l Sulfuric acid (H 2 SO

Common Acids Hydrochloric acid (HCl) l Muriatic acid l Sulfuric acid (H 2 SO 4) l Battery acid l Nitric acid (HNO 3) l Acetic acid (HC 2 H 3 O 2) l Vinegar l Phosphoric acid (H 3 PO 4) l Citric Acid l Lactic Acid l Ascorbic Acid l Vitamin C l Acetylsalicylic Acid l Aspirin l Stearic Acid l

Common Bases Sodium hydroxide l Lye, Caustic Soda l Calcium hydroxide l Lime l

Common Bases Sodium hydroxide l Lye, Caustic Soda l Calcium hydroxide l Lime l Magnesium hydroxide l Milk of magnesia l Ammonia l Sodium hypochlorite l Bleach l Sodium hydrogen carbonate l Baking Soda l Calcium carbonate l Chalk l Tums l

Acids and Bases l Arrhenius Definitions l Arrhenius Acid – a substance that dissociates

Acids and Bases l Arrhenius Definitions l Arrhenius Acid – a substance that dissociates and produces hydronium ions in water l Arrhenius Base – a substance that dissociates and produces hydroxide ions in water

Acids and Bases l Brønsted-Lowry Definitions l Brønsted-Lowry Acid – a substance that donates

Acids and Bases l Brønsted-Lowry Definitions l Brønsted-Lowry Acid – a substance that donates a hydrogen ion (H+) (a proton) l Brønsted-Lowry Base – a substance that accepts a hydrogen ion (H+) (a proton)

Acid and Base Definitions Overlap between the acid definitions l HCl + H 2

Acid and Base Definitions Overlap between the acid definitions l HCl + H 2 O Cl- + H 3 O+ l HCl dissociates and produces hydronium ions l. Arrhenius Acid l HCl donates an H+ to water l. Brønsted-Lowry Acid l All Arrhenius Acids are Brønsted-Lowry Acids and vice versa. l

Acid and Base Definitions l Relations between the base definitions are not as simple.

Acid and Base Definitions l Relations between the base definitions are not as simple. l Na. OH dissolves in water to form Na+ and OH- l. Arrhenius Base l Na. OH + H+ Na+ l. Brønsted-Lowry l Hydroxides + H 2 O Base are both Arrhenius and Brønsted-Lowry Bases.

Acid and Base Definitions l Non-hydroxide bases can’t be Arrhenius bases l No hydroxide

Acid and Base Definitions l Non-hydroxide bases can’t be Arrhenius bases l No hydroxide obviously… l Non-hydroxide bases will be Brønsted-Lowry bases l CO 32 - + H+ HCO 3 l NH 3 + H+ NH 4+

Acid and Base Definitions l Arrhenius acids and bases are tied to water l

Acid and Base Definitions l Arrhenius acids and bases are tied to water l Brønsted-Lowry acids and bases are not. l Brønsted-Lowry can be used to describe reactions in the gas phase or in other solvents besides water.

Acid-Base Definitions l Monoprotic acid – an acid that has one ionizable hydrogen l

Acid-Base Definitions l Monoprotic acid – an acid that has one ionizable hydrogen l HCl, HNO 3 l Diprotic acid – an acid that has two ionizable hydrogens l H 2 SO 4

Acid-Base Definitions l Triprotic acid – an acid that has three ionizable hydrogens l

Acid-Base Definitions l Triprotic acid – an acid that has three ionizable hydrogens l H 3 PO 4 l What kind of acid is acetic acid, HC 2 H 3 O 2? l Monoprotic l Typically only hydrogens written first are ionizable.

l Water Autolysis of Water spontaneously splits itself l 2 H 2 O ⇌

l Water Autolysis of Water spontaneously splits itself l 2 H 2 O ⇌ H 3 O+ + OH– l An equilibrium system. l Makes equal parts hydronium and hydroxide l Equal parts acid and base l Water is neutral.

Autolysis of Water l We will use brackets to represent molarity l [H 3

Autolysis of Water l We will use brackets to represent molarity l [H 3 O+] is the molarity of the hydronium ion. l When acids and bases are dissolved in water [H 3 O+][OH–] = Kw = 1 x 10 -14

Acid Base Reactions l Look on your reference table l Most acid base reactions

Acid Base Reactions l Look on your reference table l Most acid base reactions fall under the category of double replacement; however, there are some that do not. l We are only going to consider the ones that are double replacement!

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A +

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A + HB l Transfer l of hydrogen ions (H+) Hydrochloric acid and sodium hydroxide solutions are mixed

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A +

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A + HB l Transfer l of hydrogen ions (H+) Acetic acid and barium hydroxide solutions are mixed.

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A +

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A + HB l Transfer l of hydrogen ions (H+) Ammonia and sulfuric acid solutions are mixed

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A +

Acid Base Reactions l Acid Base Neutralization Reaction l HA + B A + HB l Transfer l of hydrogen ions (H+) Hydrochloric acid and sodium sulfide solutions are mixed.

l Hydrochloric Acids acid l Is it an electrolyte? l Why is it an

l Hydrochloric Acids acid l Is it an electrolyte? l Why is it an electrolyte? l Acetic l Is acid it an electrolyte? l Why is it an electrolyte? l Why doesn’t it light up as much as hydrochloric acid?

Strength of Acids and Bases l Hydrochloric dissociates l HCl acid completely + H

Strength of Acids and Bases l Hydrochloric dissociates l HCl acid completely + H 2 O H 3 O+ + Cl- l Acetic acid doesn’t make as many ions l Acetic acid partially dissociates l HC 2 H 3 O 2 + H 2 O ⇌ H 3 O+ + C 2 H 3 O 2– l Around 0. 5% of acetic acid molecules make hydronium ions l Reactant side is very favored.

Strength of Acids and Bases l Strong acid or base – an acid or

Strength of Acids and Bases l Strong acid or base – an acid or base that completely reacts with water to form hydronium ions or hydroxide ions. l Strong acids – hydrochloric, sulfuric, nitric l Strong bases – Li. OH, Na. OH, KOH, Rb. OH, Cs. OH, Ca(OH)2, Sr(OH)2, Ba(OH)2

Strength of Acids and Bases l Weak acid or base – an acid or

Strength of Acids and Bases l Weak acid or base – an acid or base that partially reacts with water to form hydronium ions or hydroxide ions. l Weak acids – everything except the strong acids l Weak bases – everything except the strong bases

Strong Acid Weak Acid

Strong Acid Weak Acid

Strength of Acids and Bases l Strength does not describe concentration l Consider l.

Strength of Acids and Bases l Strength does not describe concentration l Consider l. A bottle of “glacial” acetic acid (99%) l A bottle of concentrated sulfuric acid (98%) l Both have (nearly) the same concentration l Acetic acid will not ionize as much in water as sulfuric acid will l Acetic acid is a “weak” acid

Concentration of Acids l If not all acids completely dissociate in water l The

Concentration of Acids l If not all acids completely dissociate in water l The concentration of the acid molecules is different for every acid l The concentration of the hydronium ion in different acids is different l Need a system that describes the concentration of acids.

p. H l p. H = -log [H 3 O+] Also define a relationship

p. H l p. H = -log [H 3 O+] Also define a relationship for the amount of base l p. OH = -log [OH–] l How do you reverse a log? l 10 -p. H = [H 3 O+] l 10 -p. OH = [OH–] l

How are p. H and p. OH related? Kw = [H 3 O+][OH–] log

How are p. H and p. OH related? Kw = [H 3 O+][OH–] log Kw = log ([H 3 O+][OH–]) log Kw = log [H 3 O+] + log [OH–] log 1 x 10 -14 = log [H 3 O+] + log [OH–] 14 = -log [H 3 O+] + -log [OH–] 14 = p. H + p. OH

Practice Problems l What is the p. H of a solution with [H+] of

Practice Problems l What is the p. H of a solution with [H+] of 1. 0 x 10 -3 M?

Practice Problems l What is the p. OH of a solution with [H+] of

Practice Problems l What is the p. OH of a solution with [H+] of 1. 0 x 10 -3 M?

Practice Problems l What is the [OH-] of a solution with a p. H

Practice Problems l What is the [OH-] of a solution with a p. H of 9. 00?

Practice Problems l What is the [OH-] of a solution with an [H 3

Practice Problems l What is the [OH-] of a solution with an [H 3 O+] concentration of 1. 0 x 10 -5 M?

Practice Problems l What is the p. H of a solution with a hydronium

Practice Problems l What is the p. H of a solution with a hydronium ion concentration of 2. 55 x 10 -4 M?

Practice Problems l What is the p. OH of a solution that has a

Practice Problems l What is the p. OH of a solution that has a hydronium ion concentration of 5. 50 x 10 -8 M?

Indicators Colored compounds that are sensitive to changes in p. H l Indicators will

Indicators Colored compounds that are sensitive to changes in p. H l Indicators will change color based on how acidic or basic the conditions around it are l l Chemical reaction with the acids or bases

Universal Indicator l Universal Indicator is a mixture of different indicators. l Resulting color

Universal Indicator l Universal Indicator is a mixture of different indicators. l Resulting color depends on each of the four indicator’s states

Redox Chemistry

Redox Chemistry

Electrolysis l Run a current through water. l Splits water into hydrogen and oxygen

Electrolysis l Run a current through water. l Splits water into hydrogen and oxygen l 2 H 2 O 2 H 2 + O 2

Oxidation Numbers l Describes the relative amount of electrons associated with a particular atom

Oxidation Numbers l Describes the relative amount of electrons associated with a particular atom l Has no actual physical meaning (for the most part) l Only an electron bookkeeping method.

Finding Oxidation Numbers 1. 2. Every uncombined element in its natural state has an

Finding Oxidation Numbers 1. 2. Every uncombined element in its natural state has an oxidation number of zero. The oxidation number of a monatomic ion is its charge.

Finding Oxidation Numbers 3. Remember the following: l l l 4. Fluorine in a

Finding Oxidation Numbers 3. Remember the following: l l l 4. Fluorine in a compound is always -1 Hydrogen is a +1 normally in a compound. It is -1 when a hydride. Oxygen is almost always -2 in a compound unless it is a peroxide (-1) The sum of the individual oxidation numbers on every atom in a species is equal to the overall charge on that species.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. CHF 3

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. Ba. Cl 2

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. KNO 3

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. S 2 O 32 -

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. P 4

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds.

Oxidation Numbers Practice Give the oxidation number of every element in the following compounds. (NH 4)2 C 2 O 4

Oxidation and Reduction Oxidation - chemical process involving the loss of electrons. l Reduction

Oxidation and Reduction Oxidation - chemical process involving the loss of electrons. l Reduction – chemical process involving gaining electrons. l LEO the lion goes GER l OIL RIG l

Oxidation and Reduction l Consider: Mn. O 4 - + C 2 O 42

Oxidation and Reduction l Consider: Mn. O 4 - + C 2 O 42 - + H+ Mn 2+ + CO 2 + H 2 O What element has been reduced? l What element has been oxidized? l What species reacted with the element that was reduced? l l This l is the reducing agent. What species reacted with the element that was oxidized? l This is the oxidizing agent.

Vanadium Oxidation States l Vanadium oxidation states. mov

Vanadium Oxidation States l Vanadium oxidation states. mov

Practice l Identify the element oxidized, the element reduced, the species that is the

Practice l Identify the element oxidized, the element reduced, the species that is the oxidizing agent, and the species that is the reducing agent in: I- + Cl. O- + H+ I 3 - + Cl- + H 2 O

Practice l Identify the element oxidized, the element reduced, the species that is the

Practice l Identify the element oxidized, the element reduced, the species that is the oxidizing agent, and the species that is the reducing agent in: H+ + Cr 2 O 72 - + C 2 H 5 OH Cr 3+ + CO 2 +H 2 O

Uses of Redox Chemistry Batteries l Harnessed flow of electrons driven by redox reaction.

Uses of Redox Chemistry Batteries l Harnessed flow of electrons driven by redox reaction. Car battery Pb. O 2(s) + Pb(s) + 2 H 2 SO 4 2 Pb. SO 4(s) + 2 H 2 O

Alkaline Batteries Zn + 2 Mn. O 2 Zn. O + Mn 2 O

Alkaline Batteries Zn + 2 Mn. O 2 Zn. O + Mn 2 O 3

Fuel Cells l 2 H 2 + O 2 2 H 2 O

Fuel Cells l 2 H 2 + O 2 2 H 2 O

Electroplating

Electroplating

Corrosion

Corrosion