Chem II: Block Infinite Campus: Chemical Reactions Exam Replacement Labs (30pts.) Objectives: I can predict and simplify double replacement reactions. I can distinguish between oxidation and reduction reactions. I can balance oxidation-reduction (Redox) reactions.

Double Replacement Reactions Complete 4.24 problems.

Solubility Ranges Soluble: > 0.1M concentration of solute dissolved in solution. Insoluble: < M concentration of solute dissolved in solution. Slightly soluble: between M and 0.1 M of solute dissolved in solution.

Double Replacement Reactions Why is it some ionic compounds are soluble in water and others are not? Use the image below to come up with an educated guess.

Aqueous Reactions Reactions that occur in aqueous solutions: 1.Double Replacement Reactions 2.Oxidation-Reduction (Redox) Reactions 3.Acid-Base Reactions

Oxidation Reduction Reactions

Also called Redox Reactions One reactant becomes oxidized (lose electrons) and one reactant becomes reduced (gains electrons). (spontaneous /non-spontaneous). Transfer of electrons from the oxidized reactant to the reduced reactant.

LEO goes GER LEO: lose electron(s) oxidized GER: gain electron(s) reduced animals.nationalgeographic.com

Redox Reactions Ex. 2Ca + O > 2CaO How do you know which reactant is oxidized (LEO) and which reactant is reduced (REO) in a redox reaction? Assigning oxidation numbers for elements in the reaction.

Oxidation Number Rules 1. For an atom that is not combined with any other kind of atom its oxidation number is zero. Ex. Mg 0, Fe 0, H 2 0 (all diatomic molecules) 2.A monatomic ion’s oxidation number is equal to its charge. Ex. Mg 2 = oxidation number is 2+ Cl 1- = oxidation number is 1-

Oxidation Number Rules 3. The sum of the oxidation number for all atoms in a compound (ionic or covalent) is zero. Ex. H 2 1 O -2 = zero Ex. NaCl 1- = zero

Oxidation Number Rules 4. The oxidation number for oxygen in a compound is -2. Ex. C 4 O 2 2- *Exceptions: a.peroxides (O 2 ) 2- the oxidation number is -1 Ex. H 2 1 O 2 1- a.Bonded to F: oxidation number is positive (1 + or 2 + ) Ex. O 1+ F 1- F > O electronegativity

Electronegativity Values

Oxidation Number Rules 5. Hydrogen: When bonded to a non-metal it is 1+ (most common) Ex. H 1 Cl 1- When bonded to a metal it will be 1-. Ex. Mg 2+ H 2 1

Oxidation Number Rules 6. Polyatomic Ions: The sum of the oxidation numbers of all atoms in a polyatomic ion has to equal the charge on that ion. Ex. (Cl 5 O 3 2- ) 1-

Oxidation Number Rules 7.In covalent compounds that do not contain hydrogen or oxygen, the most electronegative element has an oxidation number equal to its charge as an ion. Ex. P 5 Cl 5 1-, Cl> P with electronegativity

Electronegativity Values

Chem II: Block Infinite Campus: Chemical Reactions Exam Replacement Labs Due: Element’s Oxdiation #s: qts. 4.49; 4.50 from text Objectives: I can distinguish between oxidation and reduction reactions using oxidations numbers. I can balance oxidation-reduction (Redox) reactions.

Oxidation Numbers: qts a.SO 2 b.COCl 2 c. (MnO 4 ) - : Mn =7+ O = 2- d. H(BrO): O = 2-; Br= -1; H = +1 *(BrO) 1- =hypobromite ion e.As 4 f. K 2 O 2 : O = 1- (peroxide ion); K= 1+

Oxidation Numbers: 4.50 a. b. c. d. e. f.

Oxidation Numbers: Assessment Assign an oxidation number for each element in the examples below: 1. H 2 2. Cu 3. Fe 2 O 3 4. N 2 O 5 5. H(NO 3 ) 6. CCl 4 8. Cr(CO 3 ) 9. OF Ca(OH) 2

Oxidation Numbers: Assessment Assign an oxidation number for each element in the examples below: 1. H 2 2. Cu 3. Fe 2 O 3 4. N 2 O 5 5. H(NO 3 ) 6. CCl 4 8. Cr(CO 3 ) 9. OF Ca(OH) 2

Chem II: Block Due: Oxidation/Reduction Worksheet Objectives: I can distinguish between oxidation and reduction reactions using oxidations numbers. I can balance oxidation-reduction (Redox) reactions.

Redox Reactions Ex. 2Ca + O > 2CaO a.Assign oxidation numbers for each element on on reactant and products side. b.Identify and explain which element was reduced in this reaction. c.Identify and explain which element was oxidized in this reaction.

Redox Reactions: Half Reactions Ex. 2Ca + O > 2CaO Half-Reactions: Separates/identifies the oxidized and reduced reactions that occur simultaneously in nature-why called Redox reactions. Oxidized Reaction: Reduced Reaction:

Redox Reactions Practice Problems 1. Classify each half reaction as oxidation or reduction. a. Ba ----> Ba e- b. 2H e > H 2 2. Using oxidation numbers, predict if the reactions below are redox reactions. a. Fe (s) + Cu(SO 4 ) (aq) ----> Fe(SO 4 ) (aq) + Cu (s) b. NaCl (aq) + Ag(NO 3 ) (aq) ---> Na(NO 3 ) (aq) + AgCl (s)

Redox Reactions: Half-Reactions

Balancing Redox Reactions Must conserve mass and charge. Establish half reactions to ensure electron transfer is balanced. Only include substances undergoing redox in the half-reactions. Redox reactions usually occur in acidic or basic solutions. (Balance differently).

Balancing Redox Reactions: Acidic Solutions Cu (s) + NO 3- (aq) ----> Cu 2+ (aq) + NO 2 (g)

Chem II: 9/24 Objectives: I can predict redox reactions by assessing oxdiation numbers of elements in the reaction. I can balance redox reactions using half reactions. Homework: Balance Redox Reactions (Acidic/Basic) Redox Quiz tomorrow

Redox Reactions Ag(NO 3 ) + Cu --> a.Predict Products b.Assign Oxidation Numbers to validate if redox reaction. c.If redox, identify and explain what is oxidized and what is reduced.

Balancing Redox Reactions: Acidic Cu (s) + NO 3- (aq) ----> Cu 2+ (aq) + NO 2 (g)

Balancing Redox Reactions: Acidic (Cr 2 O 7 ) -2 (aq) + I - (aq)----> Cr 3+ (aq) + (IO 3 ) - (aq)

Balancing Redox Reactions Balance half reactions with peers via gallery walk. Self-assess peers work by making changes where needed. Record your answers on a separate sheet of paper.

Chem II: 9/25 Objectives: I can predict redox reactions by assessing oxdiation numbers of elements in a reaction. (Quiz today) I can balance redox reactions using half reactions in acidic or basic solutions. Review Chemical Reaction Exam Homework: Balance Redox Reactions (Acidic/Basic)

Balancing Half Reactions

Balancing Redox Reactions: Acidic (Cr 2 O 7 ) -2 (aq) + I - (aq)----> Cr 3+ (aq) + (IO 3 ) - (aq)

Chem II: 9/26 Objectives: I can balance redox reactions using half reactions in acidic or basic solutions. Review Chemical Reaction Exam Homework: Balance Redox Reactions (Acidic/Basic)

Redox Reactions: Gallery Walk

Chem II: 9/27 Objectives: I can balance redox reactions using half reactions in acidic or basic solutions. Review Chemical Reaction Exam Homework: Balance Redox Reactions (Acidic/Basic)

Balance Redox Reaction (acidic) Balance using half reactions the following reaction in acidic solution : example d

Redox Reaction (basic solution)

Balancing Redox Reactions: Basic NO 2 - (aq) + Al(s) -----> NH 3 (aq) + Al(OH) 4 - (aq)

Chem II: 9/30 Infinite Campus Update: Redox Classification Quiz -17pts Balance Redox Rxtn (acidic)-5pts Objectives: I can balance redox reactions using half reactions in acidic or basic solutions. Review Redox Reaction Quiz and Bell Ringer Review Chemical Reaction Exam Set-up Redox Lab (Use Buret for titration) Homework: Balance Redox Reactions

Midterm Exam Concepts Molarity vs. Molalilty Classification of Mixtures (colloids, suspensions, solutions) Assigning Oxidation Numbers to substances Identifying and Balancing Redox Reactions Stoichiometric Calculations with Redox Reactions

Balancing Redox Reaction (basic) Gallery Walk: Balancing Redox Reaction in basic solution.

Bell Ringer: Redox Reaction. (acidic)

Redox Classification Quiz

Chem II: 10/1 Objectives: I can balance redox reactions using half reactions in acidic or basic solutions. Review Chemical Reaction Exam Set-up Redox Reaction Lab Homework: Read procedures and complete pre-lab questions

Chemical Reaction Exam

Balancing Redox Reactions (Basic) NO 2 - (aq) + Al(s) ----> NH 4 + (aq) + AlO 2 - (aq)

Balancing Complete Redox Reactions H 2 S + H(NO 3 ) -----> S + NO + H 2 O (acidic)

Redox Titration Lab H 2 O 2 + KMnO 4 + H 2 (SO 4 )  Mn(SO 4 ) + K 2 (SO 4 ) + O 2 + H 2 O Pre-Lab: 1.Practice reading and working stopper on Buret. (Measure out 15 mL of water 3xs from buret, validate volume with graduated cylinder. 2. Complete pre-lab questions from lab

Chem II: 10/2 Objectives: Complete and assess Redox Lab Homework: Complete Post Lab Questions

Chem II: 10/4 Objectives: Chemistry II Midterm Analyze Redox Reaction Lab Homework: Have a nice fall break.

Chem II: 10/14 Infinite Campus Update: Balance Redox Reaction (Basic) Quiz Redox Lab: Hydrogen Peroxide Analysis (24pts.) Chemistry Midterm Exam (35pts.) Objectives: Review Quiz and Midterm Address Redox Lab Electrochemistry : Redox Application

Balancing Redox Reactions (Basic) NO 2 - (aq) + Al(s) ----> NH 4 + (aq) + AlO 2 - (aq)

Stoichiometry 2 H 2 O + NO Al(s) ----> NH AlO 2 -

Balanced Redox Reactions (Basic) 2 H 2 O + NO Al(s) ----> NH AlO 2 - a.If we start with 3.8 moles of NO 2 - how many moles of AlO 2 - could be produced? b. If we want 13 grams of NH 4 + ion, how many grams of Al would we need to start with?

Chemistry Midterm Exam

#18. Mn 2+ (aq) + Na(BiO 3 ) (s) ---> Bi 3+ (aq) + MnO 4 -

Chemistry Midterm Exam #19. Cr(OH) 3 (s) + ClO - (aq) ---> ( CrO 4 ) 2- (aq) + Cl 2 (g)

Redox Titration Lab

Redox Titration Lab H 2 O 2 + KMnO 4 + H 2 (SO 4 )  Mn(SO 4 ) + K 2 (SO 4 ) + O 2 + H 2 O 5H 2 O 2 + 2KMnO 4 +3H 2 (SO 4 )  2Mn(SO 4 ) +K 2 (SO 4 ) + 5 O 2 + 8H 2 O

Redox Titration Lab Results Lab GroupAvg. volume of KMnO 4 Avg: % of H 2 O 2 in solution % Error % Error :

Redox Titration Lab Results Conclusion: 1.a. How accurate was your experimental value with the actual value of % hydrogen perxoide in solution. b. Explain reasons for degree error. 2. How accurate was the class’ data from one another? 3. If you could repeat the lab what modifications would you make and why.