Day 1-8 Chemistry Lecture Notes PDF

Agenda Day 1 - Physical vs chemical changes - Balancing a chemical reaction Intermolecular Forces © 2015 Pearson Education, Inc.  Types of...

Agenda Day 1 - Physical vs chemical changes - Balancing a chemical reaction Intermolecular Forces © 2015 Pearson Education, Inc.  Types of Changes Physical Changes are changes in matter that do not change the composition of a substance. Chemical Changes result in new substances. Bonds are broken and new bonds are formed. Matter And Measurement © 2015 Pearson Education, Inc.  Changes in State of Matter Converting between the three states of matter is a physical change. When ice melts or water evaporates, there are still 2 H atoms and 1 O atom in each molecule. Matter And Measurement © 2015 Pearson Education, Inc. Chemical Reactions (Chemical Change) In the course of a chemical reaction, the reacting substances are converted to new substances. Here, the elements hydrogen and oxygen become water. Matter And Measurement © 2015 Pearson Education, Inc.  Signs a chemical change MAY have occurred Evolution of gas Formation of precipitate Evolution of heat, light or sound Matter And Measurement © 2015 Pearson Education, Inc.  Chemical Equations Chemical equations are concise representations of chemical reactions. Matter And Measurement © 2015 Pearson Education, Inc.  3.1 Chemical Equations Depict the kind of reactants and products and their relative amounts in a reaction. 4 Al(s) + 3 O2(g) → 2 Al2O3(s) The numbers in the front are called stoichiometric coefficients The letters (s), (g), and (s) are the physical states of compounds.  Reaction of Phosphorus with Cl2 Notice the stoichiometric coefficients and the physical states of the reactants and products.  Reaction of Iron with Cl2 Notice the stoichiometric coefficients and the physical states of the reactants and products.  Chemical Equations 4 Al(s) + 3 O2(g) → 2 Al2O3(s) This equation means 4 Al atoms + 3 O2 molecules → 2 “molecules” of Al2O3 -or- 4 moles Al + 3 moles O2 → 2 moles of Al2O3  Chemical Equations Because the same atoms are present in a reaction at the beginning and at the end, the amount of matter in a system does not change. The Law of the Conservation of Matter _?_ HgO (s) → _?_ Hg (lq) + _?_ O2(g)  Chemical Equations Because the same atoms are present in a reaction at the beginning and at the end, the amount of matter in a system does not change. The Law of the Conservation of Matter _2_ HgO (s) → _2_ Hg (lq) + __ O2(g) (chemists are lazy so we don’t write  Balance only one element at a time, leave oxygen and hydrogen to balance last. Don’t change chemical formulas (subscripts), only place numbers in front (coefficients) Reduce the coefficients to the lowest ratio Polyatomic ions that remain unchanged from reactant side to product side, keep as a polyatomic ion and balance these first. If hydroxide appears on one side of the equation and water on the other side, you can rewrite water as HOH. Balance single elements last If the reaction only involves C, H, and O’s; balance alphabetically Stoichiometry © 2015 Pearson Education, Inc.  3.1 Balancing Equations ____C3H8(g) + _____ O2(g) → _____CO2(g) + _____ H2O(g) ____B4H10(g) + _____ O2(g) → ___ B2O3(g) + _____ H2O(g) How to master balancing equations??? Practice!  Practice worksheet Matter And Measurement © 2015 Pearson Education, Inc.  Homework Day 1 Your homework for tonight will be to complete: (1)Book Reading- posted on google classroom (2)Book Problems- posted on google classroom (3)AP Classroom videos Basic Concepts of Chemical Bonding © 2015 Pearson Education, Inc.  DO NOW Balance the following eqs: a) Li (s) + N2 (g) → Li3N (s) b) TiCl4 (l) + H2O (l) → TiO2 (s) + HCl (g) © 2015 Pearson Education, Inc.  DO NOW Balance the following eqs: a) 6 Li (s) + N2 (g) → 2 Li3N (s) b) TiCl4 (l) + 2 H2O (l) → TiO2 (s) + 4 HCl (g) © 2015 Pearson Education, Inc.  AP Question A student was studying physical and chemical changes. The student carried out some procedures in the laboratory and recorded observations. For one of the procedures, the student concluded that a physical change took place, but not a chemical change. Which of the following could have been the results of the procedure? a- A cube of metal was changed into a flat sheet of metal. b- When two liquids at room temperature were combined in a beaker, the beaker became hot. c- When two clear liquids were combined, the resulting mixture was cloudy. Matter d- When a colorless liquid was added to a blue liquid, the And resulting solution was yellow. Measurement © 2015 Pearson Education, Inc.  AP Question A student was studying physical and chemical changes. The student carried out some procedures in the laboratory and recorded observations. For one of the procedures, the student concluded that a physical change took place, but not a chemical change. Which of the following could have been the results of the procedure? a- A cube of metal was changed into a flat sheet of metal. b- When two liquids at room temperature were combined in a beaker, the beaker became hot. c- When two clear liquids were combined, the resulting mixture was cloudy. Matter And d- When a colorless liquid was added to a blue liquid, the Measurement © 2015 Pearson Education, Inc.  Agenda Day 2 - Solubility rules - Net Ionic Equations Intermolecular Forces © 2015 Pearson Education, Inc.  Announcement You will have a quiz over Day 1-8 on Friday, December 13th Aqueous Reactions © 2015 Pearson Education, Inc.  Solubility of Ionic Compounds Not all ionic compounds dissolve in water. A list of solubility rules is used to decide what combination of ions will dissolve. See page 129 of textbook. For the AP exam, memorize that all nitrates, Group 1A metals, acetate, and ammonium salts are all soluble Aqueous Reactions © 2015 Pearson Education, Inc.  Aqueous Reactions © 2015 Pearson Education, Inc. Determine if the follow salts are soluble or insoluble: NH4Cl CaCO3 NaOH Mg(OH)2 Aqueous Reactions Ca(CH 3COO) © 2015 Pearson Education,2 Inc. AgCl  Precipitation Reactions When two solutions containing soluble salts are mixed, sometimes an insoluble salt will be produced. A salt “falls” out of solution, like snow out of the sky. This solid is called a precipitate. Aqueous Reactions © 2015 Pearson Education, Inc.  Molecular Equation The molecular equation lists the reactants and products without indicating the ionic nature of the compounds. AgNO3(aq) + KCl(aq) ⎯→ AgCl(s) + KNO3(aq) Aqueous Reactions © 2015 Pearson Education, Inc.  Complete Ionic Equation In the complete ionic equation all strong electrolytes (strong acids, strong bases, and soluble ionic salts) are dissociated into their ions. This more accurately reflects the species that are found in the reaction mixture. Ag+(aq) + NO3−(aq) + K+(aq) + Cl−(aq) ⎯→ AgCl(s) + K+(aq) + NO3−(aq) Aqueous Reactions © 2015 Pearson Education, Inc.  Net Ionic Equation To form the net ionic equation, cross out anything that does not change from the left side of the equation to the right. The ions crossed out are called spectator ions, K+ and NO3−, in this example. The remaining ions are the reactants that form the product—an insoluble salt in a precipitation reaction, as in this example. Ag+(aq) + NO3−(aq) + K+(aq) + Cl−(aq) ⎯→ AgCl(s) + K+(aq) + NO3−(aq) Aqueous Reactions © 2015 Pearson Education, Inc.  Writing Net Ionic Equations 1. Write a balanced molecular equation. 2. Dissociate all strong electrolytes. 3. Cross out anything that remains unchanged from the left side to the right side of the equation. 4. Write the net ionic equation with the species that remain. Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Write the net ionic equation for the reaction of BaCl2 and K2SO4 to form aqueous KCl and solid BaSO4 Aqueous Reactions © 2015 Pearson Education, Inc.  Net Ionic Equations remember to balance the eqn first! 1. BaCl2(aq) + Na2SO4(aq) → NaCl (aq) + BaSO4(s) 2. (NH4)2S(aq) + Mg(NO3)2(aq) → MgS(s) + NH4NO3(aq) 3. ZnBr2(aq) + Na2CO3(aq) → ZnCO3(s) + NaBr (aq) Aqueous Reactions © 2015 Pearson Education, Inc.  Net Ionic Equations remember to balance the eqn first! 1. BaCl2(aq) + Na2SO4(aq) → NaCl (aq) + BaSO4(s) Ba2+ (aq) + SO42- (aq) → BaSO4 2. (NH4)2S(aq) + Mg(NO3)2(aq) → MgS(s) + NH4(NO3)2(aq) S2- (aq) + Mg2+ (aq) → MgS (s) 3. ZnBr2(aq) + Na2CO3(aq) → ZnCO3(s) + NaBr (aq) Aqueous Reactions Zn 2+ (aq) © 2015 Pearson Education, Inc. + CO 3 2- (aq) → ZnCO3 (s)  Neutralization Reactions When a strong acid (like HCl) reacts with a strong base (like NaOH), the reaction produces water instead of a precipitate, the net ionic equation is circled below: HCl(aq) + NaOH(aq) ⎯→ NaCl(aq) + H2O(l) H+(aq) + Cl−(aq) + Na+(aq) + OH−(aq) ⎯→ Na+(aq) + Cl−(aq) + H2O(l) H+(aq) + OH−(aq) ⎯→ H2O(l) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem For the reaction of aqueous HCl and aqueous Ba(OH)2 to form BaCl2 and water write the molecular equation net ionic equation Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem For the reaction of aqueous HCl and aqueous Ba(OH)2 to form BaCl2 and water write the molecular equation 2 HCl (aq) + Ba(OH)2 (aq) → 2H2O(l) + BaCl2(aq) net ionic equation H+ (aq) + OH - (aq) → H2O (l) Aqueous Reactions © 2015 Pearson Education, Inc.  Double Replacement: Gas-Forming Reactions When a carbonate or bicarbonate reacts with an acid, the products are a salt, carbon dioxide, and water. CaCO3(s) + 2 HCl(aq) ⎯→CaCl2(aq) + CO2(g) + H2O(l) NaHCO3(aq) + HBr(aq) ⎯→NaBr(aq) + CO2(g) + H2O(l) Aqueous Reactions © 2015 Pearson Education, Inc.  Net Ionic Equations 1. K2CO3(aq) + HCl(aq) → KCl (aq) + H2O(l) + CO2 (g) 2. CaCO3(s) + HNO3(aq) → Ca(NO3)2(aq) + H2O(l) + CO2(g) 3. HCl(aq) + NaOH(aq) → H2O (l) + NaCl (aq) Aqueous Reactions © 2015 Pearson Education, Inc.  Write a net ionic equation for: 1. CaCl2(aq) + K2SO4(aq) → 2 KCl (aq) + CaSO4(s) 2. Na2S(aq) + Ba(NO3)2(aq) → BaS(s) + 2 NaNO3(aq) Intermolecular Forces © 2015 Pearson Education, Inc.  solubility rules practice Aqueous Reactions © 2015 Pearson Education, Inc.  Net ionic Equations practice #1-6 is homework Aqueous Reactions © 2015 Pearson Education, Inc.  DO NOW Use your solubility chart to predict the precipitate formed and write a net ionic equation for the reaction. AgNO3 ( ) + KCl ( ) → AgCl ( ) + KNO3 ( ) Write a net ionic equation for: NaHCO3(aq) + HBr(aq) →NaBr(aq) + CO2(g) + H2O(l)  DO NOW Use your solubility chart to predict the precipitate formed. Write a net ionic equation. AgNO3(aq) + KCl (aq) → AgCl (s) + KNO3(aq) Ag+(aq) + Cl- (aq) → AgCl (s) NaHCO3(aq) + HBr(aq) →NaBr(aq) + CO2(g) + H2O(l) HCO3- (aq) + H+(aq) → CO2(g) + H2O(l)  Agenda Day 3 - Types of reactions pt 1 Intermolecular Forces © 2015 Pearson Education, Inc.  Types of Reactions - pt 1 There are three types of chemical reactions we will talk about today: 1. Synthesis reactions 2. Decomposition reactions 3. Combustion reactions Intermolecular Forces © 2015 Pearson Education, Inc.  Steps to Writing Reactions Some steps for doing reactions 1. Identify the type of reaction 2. Predict the product(s) using the type of reaction as a model. For the state of matter, use the periodic table if it’s an element. If it’s an ionic compound, it will be a solid (ionic compounds have high m.p.) 3. Balance it Don’t forget about the diatomic elements! Intermolecular Forces For example, Oxygen is O2 as an element. © 2015 Pearson Education, Inc.  1. Synthesis reactions Synthesis reactions occur when two substances (generally elements) combine and form a compound. (Sometimes these are called combination or addition reactions.) reactant + reactant → 1 product Basically: A + B → AB Example: 2H2 (g)+ O2 (g) → 2H2O (l) Example: C (s)+ O2 (g)→ CO2 (g) Intermolecular Forces © 2015 Pearson Education, Inc.  Synthesis Reactions Here is another example of a synthesis reaction Intermolecular Forces © 2015 Pearson Education, Inc.  Practice Predict the products. Write and balance the following synthesis reaction equations. Sodium metal reacts with chlorine gas Na(s) + Cl2(g) → Solid Magnesium reacts with fluorine gas Mg(s) + F2(g) → Intermolecular Forces © 2015 Pearson Education, Inc.  Practice Predict the products. Write and balance the following synthesis reaction equations. Sodium metal reacts with chlorine gas 2 Na(s) + Cl2(g) → 2 NaCl (s) Solid Magnesium reacts with fluorine gas Mg(s) + F2(g) → MgF2 (s) Intermolecular Forces © 2015 Pearson Education, Inc.  2. Decomposition Decomposition reactions occur Reactions when a compound breaks up into the elements or in a few to simpler compounds. Heat is often added to initiate a decomposition reaction. This is shown with a triangle above the arrow. 1 Reactant → Product + Product In general: AB → A + B Example: 2 H2O → 2H2 + O2 Intermolecular Forces © 2015 Pearson Education, Inc.  Decomposition Reactions Another view of a decomposition reaction: Intermolecular Forces © 2015 Pearson Education, Inc.  Practice Predict the products. Then, write and balance the following decomposition reaction equations: Sodium chloride decomposes NaCl(s) → Aluminum nitride decomposes AlN(s) → Intermolecular Forces © 2015 Pearson Education, Inc.  Practice Predict the products. Then, write and balance the following decomposition reaction equations: Solid Lead (IV) oxide decomposes 2 NaCl(s) → 2 Na (s) + Cl2 (g) Aluminum nitride decomposes 2 AlN(s) → 2 Al (s) + N2 (g) Intermolecular Forces © 2015 Pearson Education, Inc.  3. Combustion Reactions Combustion reactions occur when a hydrocarbon reacts with oxygen gas. This is also called burning!!! In order to burn something you need the 3 things in the “fire triangle”: 1) A Fuel (hydrocarbon) 2) Oxygen to burn it with Intermolecular Forces 3) Something to ignite © 2015 Pearson Education, Inc.  Combustion Reactions In general: CxHy ( g or l) + O2 (g) → CO2 (g)+ H2O(g) Products in combustion are ALWAYS carbon dioxide and water. (although incomplete burning does cause some by- products like carbon monoxide) Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C8H18) Intermolecular state of matter for hydrocarbon Forces would have to be given © 2015 Pearson Education, Inc.  Combustion Example C5H12 (l) + 8 O2(g) → 5 CO2(g) + 6 H2O (g) Write the products and balance the following combustion reaction: C10H22 (l) + O2 (g) → Intermolecular Forces © 2015 Pearson Education, Inc.  Combustion Example C5H12 (l) + 8 O2 (g) → 5 CO2 (g)+ 6 H2O (g) Write the products and balance the following combustion reaction: 2 C10H22 (l)+ 31 O2(g) → 20 CO2 (g)+ 22 H2O (g) Intermolecular Forces © 2015 Pearson Education, Inc.  Practice- key is posted on google classroom Intermolecular Forces © 2015 Pearson Education, Inc.  Homework Day 3 Your homework for tonight will be to complete: (1)Book Reading- posted on google classroom (2)Book Problems- posted on google classroom (3)AP Classroom videos Basic Concepts of Chemical Bonding © 2015 Pearson Education, Inc.  DO NOW- Write a balanced equation for each of the following reactions. Be sure to include states of matter. 1. The reaction between Li and F2 2. MgS decomposes into the elements 3. Al metal combines with O2 gas Modern Materials © 2015 Pearson Education, Inc.  DO NOW- Write a balanced equation for each of the following reactions. Be sure to include states of matter. 1. The reaction between Li and F2 2 Li (s) + F2 (g) →2 LiF (s) 2. MgS decomposes into the elements MgS (s) → Mg (s) + S (s) 3. Al metal combines with O2 gas 4 Al (s) + 3 O2 (g) → 2 Al2O3 (s)Materials Modern © 2015 Pearson Education, Inc.  Agenda Day 4 - Double replacement reactions precipitation neutralization gas forming Intermolecular Forces © 2015 Pearson Education, Inc.  Precipitation Reactions When two solutions containing soluble salts are mixed, sometimes an insoluble salt will be produced. A salt “falls” out of solution, like snow out of the sky. This solid is called a precipitate. Aqueous Reactions © 2015 Pearson Education, Inc.  Double Replacement: Precipitation Reactions Aqueous Reactions © 2015 Pearson Education, Inc.  (Exchange) Reactions OR Double Replacement Reactions It appears as though the ions in the reactant compounds exchange ions, as seen in the equation below. AgNO3(aq) + KCl(aq) ⎯→ AgCl(s) + KNO3(aq) Aqueous Reactions © 2015 Pearson Education, Inc.  Completing and Balancing Metathesis Equations 1) Use the chemical formulas of the reactants to determine which ions are present. If one of the reactants contains a transition metal, use the formula in the reactant to figure out the charge. 2) Write formulas for the products: cation from one reactant, anion from the other. Use charges to write proper subscripts. 3) Check your solubility rules. If either product is insoluble, a precipitate forms. Aqueous Reactions 4) Balance the equation. © 2015 Pearson Education, Inc.  Practice Problem Write the balanced chemical equation for the reaction of BaCl2 and K2SO4 in water Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Write the balanced chemical equation for the reaction of BaCl2 and K2SO4 in water BaCl2 (aq) + K2SO4 (aq) → 2 KCl (aq) + BaSO4(s) Aqueous Reactions © 2015 Pearson Education, Inc.  Ways to Write Double Replacement Reactions 1) Molecular equation 2) Complete ionic equation 3) Net ionic equation Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Write the net ionic equation for the reaction of BaCl2 and K2SO4 in water Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Write the balanced chemical equation for the reaction of BaCl2 and K2SO4 in water BaCl2 (aq) + K2SO4 (aq) → 2 KCl (aq) + BaSO4(s) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Write the net ionic equation for the reaction of BaCl2 and K2SO4 in water Ba2+(aq) + SO42-(aq) → BaSO4(s) Aqueous Reactions © 2015 Pearson Education, Inc.  Net Ionic Equations 4. BaCl2(aq) + Na2SO4(aq) → 6. ZnBr2(aq) + Na2CO3(aq) → 5. (NH4)2S(aq) + Mg(NO3)2(aq) → Aqueous Reactions © 2015 Pearson Education, Inc.  Net Ionic Equations 4. BaCl2(aq) + Na2SO4(aq) → Ba2+ (aq) + SO42- (aq) → BaSO4 (s) 6. ZnBr2(aq) + Na2CO3(aq) → Zn2+ (aq) + CO32- (aq) → ZnCO3(s) 7. (NH4)2S(aq) + Mg(NO3)2(aq) → Mg2+ (aq) + S2- (aq) → MgS (s) Aqueous Reactions © 2015 Pearson Education, Inc.  Neutralization Reactions In an acid base reaction, the acid donates a proton to the base. When a strong acid (like HCl) reacts with a strong base (like NaOH), the net ionic equation is circled below. A salt and water are always the products: HCl(aq) + NaOH(aq) ⎯→ NaCl(aq) + H2O(l) H+(aq) + Cl−(aq) + Na+(aq) + OH−(aq) ⎯→ Na+(aq) + Cl−(aq) + H2O(l) H+(aq) + OH−(aq) ⎯→ H2O(l) Aqueous Reactions © 2015 Pearson Education, Inc.  Double Replacement: Gas-Forming Reactions When a carbonate or bicarbonate reacts with an acid, the products are a salt, carbon dioxide, and water. CaCO3(s) + 2 HCl(aq) ⎯→CaCl2(aq) + H2CO3(aq) CaCO3(s) + 2 HCl(aq) ⎯→CaCl2(aq) + CO2(g) + H2O(l) NaHCO3(aq) + HBr(aq) ⎯→NaBr(aq) + H2CO3(aq) NaHCO3(aq) + HBr(aq) ⎯→NaBr(aq) + CO2(g) + H2O(l) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice save #11-17 for tomorrow Aqueous Reactions © 2015 Pearson Education, Inc.  Homework Day 4 Your homework for tonight will be to complete: (1)Book Reading- posted on google classroom (2)Book Problems- posted on google classroom (3)AP Classroom videos Basic Concepts of Chemical Bonding © 2015 Pearson Education, Inc.  DO NOW- AP question Pb(NO3)2 and KBr are combined and a yellow precipitate forms. Which of the following is the net ionic equation for the reaction? a- Pb2+ (aq) + 2Br- (aq)→ PbBr2(s) b- K+ (aq) + NO3-(aq) → KNO3 (aq) c- Pb2+ (aq) + 2Br- (aq) + 2K+ (aq) + 2NO3- (aq) → PbBr2 (s) + 2K+ (aq) + 2NO3- (aq) d- Pb(NO3)2(aq) + 2KBr(aq) → PbBr2 (s) + 2KNOBasic 3 Concepts of Chemical (aq) Bonding © 2015 Pearson Education, Inc.  DO NOW- AP question Pb(NO3)2 and KBr are combined and a yellow precipitate forms. Which of the following is the net ionic equation for the reaction? a- Pb2+ (aq) + 2Br- (aq)→ PbBr2(s) b- K+ (aq) + NO3-(aq) → KNO3 (aq) c- Pb2+ (aq) + 2Br- (aq) + 2K+ (aq) + 2NO3- (aq) → PbBr2 (s) + 2K+ (aq) + 2NO3- (aq) d- Pb(NO3)2(aq) + 2KBr(aq) → PbBr2 (s) + 2KNOBasic 3 Concepts of Chemical (aq) Bonding © 2015 Pearson Education, Inc.  DO NOW- Write a balanced equation for each of the following reactions. Be sure to include states of matter. 1. The reaction between Li and F2 2. MgS decomposes into the elements 3. Al metal combines with O2 gas Modern Materials © 2015 Pearson Education, Inc.  DO NOW- Write a balanced equation for each of the following reactions. Be sure to include states of matter. 1. The reaction between Li and F2 2 Li (s) + F2 (g) →2 LiF (s) 2. MgS decomposes into the elements MgS (s) → Mg (s) + S (s) 3. Al metal combines with O2 gas 4 Al (s) + 3 O2 (g) → 2 Al2O3 (s)Materials Modern © 2015 Pearson Education, Inc.  Agenda Day 5 - Acid/Base Reactions Intermolecular Forces © 2015 Pearson Education, Inc.  Brønsted–Lowry Acid and Base A Brønsted–Lowry acid must have at least one removable (acidic) proton (H+) to donate. The acidic proton is the proton that is bonded to the electronegative atom (O, N, S, F, Cl etc.) A Brønsted–Lowry base must have at least one nonbonding pair of electrons to accept a proton (H+). Aci ds and © 2015 Pearson Education, Inc. Bas  Aci ds and © 2015 Pearson Education, Inc. Bas  Strong Acids There are seven strong acids to memorize HCl, HBr, HI, HNO3, H2SO4, HClO3, HClO4. These are, by definition, strong electrolytes and exist totally as ions in aqueous solution; e.g., HA + H2O → H3O+ + A– The pH of these solutions would be BELOW 7, we will discuss acids more in Unit 7 Comparing Strong and Weak Acids What is present in solution for a strong acid versus a weak acid? Strong acids completely dissociate to ions. Weak acids only partially dissociate to ions. They are weak electrolytes. Aci ds and © 2015 Pearson Education, Inc. Bas Comparing Strong and Weak Acids You will often see H+ written as H3O+ (this is because any H+ in water immediately reacts with water to form H3O+ which is called hydronium ion. ) Aci ds and © 2015 Pearson Education, Inc. Bas  Weak Acids WEAK ACIDS = weak electrolytes HCH3CO2 acetic acid H2CO3 carbonic acid Acetic acid H3PO4 phosphoric acid HF hydrofluoric acid HX(aq) ←→ H+(aq) + X-  Special Rxns. With ACIDS Nonmetal oxides can be acids CO2(aq) + H2O(s) → H2CO3(aq) SO3(aq) + H2O(s) → H2SO4(aq) and can come from  Practice Problem Rank the following acids from weakest to strongest Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Classify the following as a strong electrolyte, a weak electrolyte or a non-electrolyte a- CaCl2 b- HNO3 c- HC2H5O d- KOH e- HCOOH f- C6H12O6 Aqueous Reactions © 2015 Pearson Education, Inc.  BASES Base → OH-- in water NaOH(aq) → Na+(aq) + OH- (aq) All group 1A and group 2A metal hydroxides are strong bases  Strong Bases Strong bases are the soluble hydroxides, which are the alkali metal and heavier alkaline earth metal hydroxides (Ca2+, Sr2+, and Ba2+). Again, these substances dissociate completely in aqueous solution; e.g., MOH(aq) → M+(aq) + OH–(aq) or M(OH)2(aq) → M2+(aq) + 2 OH–(aq) The pH of these solutions would be ABOVE 7, we will discuss bases more in Unit 7 Ammonia, NH3 A Common Weak Base  Special Rxns. With BASES Metal oxides are bases CaO(s) + H2O(l) → Ca(OH)2(aq) CaO in water. Indicator shows solution is basic.  Neutralization Reactions In an acid base reaction, the acid donates a proton to the base. When a strong acid (like HCl) reacts with a strong base (like NaOH), the net ionic equation is circled below. A salt and water are always the products: HCl(aq) + NaOH(aq) ⎯→ NaCl(aq) + H2O(l) H+(aq) + Cl−(aq) + Na+(aq) + OH−(aq) ⎯→ Na+(aq) + Cl−(aq) + H2O(l) H+(aq) + OH−(aq) ⎯→ H2O(l) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem For the reaction of aqueous HCH3CO2 (a weak acid) and aqueous Ba(OH)2 write the molecular equation net ionic equation (hint: HCH3CO2 is a weak acid) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem For the reaction of aqueous HCH3CO2 (a weak acid) and aqueous Ba(OH)2 write the molecular equation 2HCH3CO2(aq) + Ba(OH)2 (aq) → 2 H2O (l) + Ba(CH3CO2)2(aq) net ionic equation (hint: HCH3CO2 is a weak acid) HCH3CO2(aq) + OH- (aq) → H2O (l) + CH3CO2-(aq) Aqueous Reactions © 2015 Pearson Education, Inc.  Double Replacement: Gas-Forming Reactions When a carbonate or bicarbonate reacts with an acid, the products are a salt, carbon dioxide, and water. CaCO3(s) + 2 HCl(aq) ⎯→CaCl2(aq) + CO2(g) + H2O(l) NaHCO3(aq) + HBr(aq) ⎯→NaBr(aq) + CO2(g) + H2O(l) Aqueous Reactions © 2015 Pearson Education, Inc.  Conjugate Acids and Bases The term conjugate means “joined together as a pair.” Reactions between acids and bases always yield their conjugate bases and acids. Aci ds and © 2015 Pearson Education, Inc. Bas  Practice Problem Which substance acts as the base in the forward reaction? Identify the conjugate acid/base pairs H2S (aq) + CH3NH2 (aq) ←→ HS- (aq) + CH3NH3 + (aq) Aci ds and © 2015 Pearson Education, Inc. Bas  Practice Problem What is the conjugate acid of: CN-, SO4 2-, H2O, HCO3 - What is the conjugate base of: HClO4, H2S, PH4+, HCO3 - Aci ds and © 2015 Pearson Education, Inc. Bas  Acid/Base practice for 19.1- do #8-15 For 19.2- do #9-15 Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Aci ds and © 2015 Pearson Education, Inc. Bas  Homework Day 5 Your homework for tonight will be to complete: (1)Book Reading- posted on google classroom (2)Book Problems- posted on google classroom (3)AP Classroom videos Basic Concepts of Chemical Bonding © 2015 Pearson Education, Inc.  DO NOW Write the net ionic equation for the reaction of KOH and HCH3CO2 in water. Don’t forget states of matter. (hint: HCH3CO2 is a weak acid) KOH ( aq ) + HCH3CO2 ( aq ) → Aqueous Reactions © 2015 Pearson Education, Inc.  DO NOW Write the net ionic equation for the reaction of KOH and HCH3CO2 in water. Don’t forget states of matter. KOH ( aq ) + HCH3CO2 ( aq ) → KCH3CO2 ( aq ) + H2O (l) net ionic: OH- (aq) + HCH3CO2 ( aq ) → CH3CO2 -( aq ) + H2O (l) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Write an equation for aqueous HSO3- acting as a base in a reaction with water. Identify the conjugate acid/base pairs Aci ds and © 2015 Pearson Education, Inc. Bas  Practice Problem Write an equation for HSO3- acting as a base in a reaction with water. HSO3- (aq) + H2O(l) → H2SO3 (aq) + OH- (aq) Base Acid Conj acid conj base Identify the conjugate acid/base pairs Aci ds and © 2015 Pearson Education, Inc. Bas  Agenda Day 6 - Redox - Single replacement rxns. Intermolecular Forces © 2015 Pearson Education, Inc.  Oxidation-Reduction Reactions Loss of electrons is oxidation. Gain of electrons is reduction. One cannot occur without the other. The reactions are often called redox reactions. Single replacement rxns (Day 7) are ALWAYS REDOX Double replacement rxns are NEVER REDOX Aqueous Reactions © 2015 Pearson Education, Inc.  Oxidation-Reduction Reactions Aqueous Reactions © 2015 Pearson Education, Inc.  REDOX REACTIONS Redox reactions are characterized by ELECTRON TRANSFER between an electron donor and electron acceptor. Transfer leads to— 1. increase in oxidation number of some element = OXIDATION- Lose Electron Oxidized 2.decrease in oxidation number of some element = REDUCTION- Gain Electron ReducedLEO GOES GER  Oxidation Numbers To determine if an oxidation–reduction reaction has occurred, we assign an oxidation number to each element in a neutral compound or charged entity. Aqueous Reactions © 2015 Pearson Education, Inc.  Elemental form Zero (0) Only 1 kind of atom present; no charge O2, Ag Neutral Sum of ox. #s of atoms/ions is zero MgO compounds Atomic ions = the charge on the atom (as an individual ion) Cu2+ Rules for assigning ox. #s Group 1A +1 in compounds LiCl Group 2A +2 in compounds CaS Fluorine (F) -1 in compounds. ALWAYS. NaF Hydrogen (H) +1 if bonded to nonmetal, -1 if bonded to metal CH / NaH Oxygen (O) -2 in most cases (exception in peroxides, = -1) H2O If binary compound, the element with greater electronegativity is SO2 assigned an ox. # same as ionic charge OF2 Polyatomic ions Ox. # is same as polyatomic ion’s charge Aqueous Reactions © 2015 Pearson Education, Inc. Note: you need to learn these!  Rules to Assign Oxidation Numbers Elements in their elemental form have an oxidation number of zero. O2 (g) or Na (s) The oxidation number of a monatomic ion is the same as its charge. Na2O (s) Na: +1 and O: -2 Aqueous Reactions © 2015 Pearson Education, Inc.  Rules to Assign Oxidation Numbers Nonmetals tend to have negative oxidation numbers, although some are positive in certain compounds or ions. – Oxygen has an oxidation number of −2, except in the peroxide ion, in which it has an oxidation number of −1. (H2O2 or K2O2) – Hydrogen is −1 when bonded to a metal, +1 when bonded to a nonmetal. (H2O vs LiH) Aqueous Reactions © 2015 Pearson Education, Inc.  Rules to Assign Oxidation Numbers Nonmetals tend to have negative oxidation numbers, although some are positive in certain compounds or ions. – Fluorine always has an oxidation number of −1. – The other halogens have an oxidation number of −1 when they are negative; they can have positive oxidation numbers, most notably in oxyanions. (H2SO4 H:+1, O:-2, S is therefore +6) Aqueous Reactions © 2015 Pearson Education, Inc.  Rules to Assign Oxidation Numbers The sum of the oxidation numbers in a neutral compound is zero. The sum of the oxidation numbers in a polyatomic ion is the charge on the ion. (NH4+ H: +1, therefore N: -3) Aqueous Reactions © 2015 Pearson Education, Inc.  OXIDATION NUMBER S NH3 N = Oxidation number of F ClO- Cl = in HF? H3PO4 P = MnO4- Mn = Cr2O72- Cr =  OXIDATION NUMBER S NH3 N = -3 Oxidation number of F ClO- Cl = in HF? +1 H3PO4 P = +5 MnO4- Mn = +7 Cr2O72- Cr = +6  Practice Problem In the following reaction, what is being oxidized? What is being reduced? 2 H2O2 (l) → 2 H2O (g) + O2 (g) Aqueous Reactions © 2015 Pearson Education, Inc.  Oxidation # Practice key  Single Replacement Reactions Single Replacement Reactions occur when one element replaces another in a compound. A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-). element + compound→ element + compound A + BC → AC + B (if A is a metal) OR A + BC → BA + C (if A is a nonmetal) (remember the cation always goes first!) When H2O splits into ions, it splits into H+ and OH- (not H+ and O-2 !!)  Single Replacement Reactions Sodium chloride (aq) reacts with fluorine gas NaCl(aq) + F2(g) → Note that fluorine replaces chlorine in the compound Aluminum metal reacts with aqueous copper (II) nitrate Al(s)+ Cu(NO3)2(aq)→  Single Replacement Reactions Sodium chloride solid reacts with fluorine gas 2 NaCl(aq) + F2(g) → 2 NaF (aq) Cl2 (g) Note that fluorine replaces chlorine in the compound Aluminum metal reacts with aqueous copper (II) nitrate 2 Al(s)+ 3 Cu(NO3)2(aq)→ 2 Al(NO3)3(aq) + 3 Cu(s)  Single Replacement Reactions Write and balance the following single replacement reaction equation: Zinc metal reacts with aqueous hydrochloric 2 acid. Zinc is always +2. Zn(s) + HCl(aq) →  Single Replacement Reactions Write and balance the following single replacement reaction equation: Zinc metal reacts with aqueous hydrochloric 2 acid Zn(s) + HCl(aq) → ZnCl2 + H2(g) Note: Zinc replaces the hydrogen ion in the reaction  For the reaction of aluminum with aqueous HBr write the molecular equation net ionic equation what is being reduced in the reaction? What is being oxidized? Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem For the reaction of aluminum with HBr write the molecular equation 2 Al(s) + 6 HBr (aq) → 2 AlBr3 (aq) + 3 H2 (g) net ionic equation 2 Al(s) + 6 H+(aq) → 2 Al+3(aq) + 3 H2 (g) Al is oxidized, H+ is reduced Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem What products form when iron (II) chloride oxidizes magnesium metal? Write the net ionic equation. Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Will iron (II) chloride oxidize magnesium metal? If so, write the net ionic equation. FeCl2(aq) + Mg (s) → MgCl2 (aq) + Fe(s) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Predict the product of the following reaction and write the net ionic equation. Don’t forget states of matter Ba ( s ) + H2O ( l ) → Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Ba ( s ) + 2 H2O ( l ) → Ba(OH)2 (aq)+ H2(g) Aqueous Reactions © 2015 Pearson Education, Inc.  Displacement Reactions OR Single Replacement Reactions In displacement reactions, ions oxidize an element. In this reaction, silver ions oxidize copper metal: Cu(s) + 2 Ag+(aq) ⎯→ Cu2+(aq) + 2 Ag(s) The reverse reaction does NOT occur. Why not? Aqueous Reactions © 2015 Pearson Education, Inc.  Activity Series- pg 144 Elements higher on the activity series are more reactive. They are more likely to exist as ions. Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Will iron (II) chloride oxidize magnesium metal? If so, write the net ionic equation. Aqueous Reactions © 2015 Pearson Education, Inc.  Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Will iron (II) chloride oxidize magnesium metal? If so, write the net ionic equation. Magnesium is higher than iron (II) on the activity series. It is more reactive and more likely to exist as an ion. The following reaction will occur: FeCl2(s) + Mg (s) → MgCl2 (aq) + Fe(s) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Use the activity series to predict if the following reaction will occur. If so, write the molecular and net ionic equation. Don’t forget states of matter Al ( s ) + H2O ( l ) → Aqueous Reactions © 2015 Pearson Education, Inc.  Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Use the activity series to predict if the following reaction will occur. If so, write the molecular and net ionic equation. Don’t forget states of matter 2 Al (s) + 6 H2O ( l ) → 2 Al(OH)3 (s)+ 3 H2(g) Aqueous Reactions © 2015 Pearson Education, Inc.  Single Replacement Practice key Aqueous Reactions © 2015 Pearson Education, Inc.  Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Pieces of tin and platinum are dropped into separate water filled test tubes (tubes A and B). Tube A bubbles vigorously while test tube B does not. Which test tube contains tin metal? How do you know? Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Pieces of tin and platinum are dropped into separate water filled test tubes (tubes A and B). Tube A bubbles vigorously while test tube B does not. Sn is higher than H2 on the activity series, Pt is not. Test tube A contains Sn and the following reaction occurs. Sn (s) + H2O (l) → H2 (g) + Sn(OH)2 (s) Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem Aqueous AgCH3CO2, Li2S, and BaCl2 are mixed. What precipitates form? Aqueous Reactions © 2015 Pearson Education, Inc.  Practice Problem AgCH3CO2, Li2S, and BaCl2 are mixed. What precipitates form? AgCl, Ag2S Aqueous Reactions © 2015 Pearson Education, Inc.  DO NOW- AP question Cu(s) + 4 HNO3(aq) → Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l) Which of the following is true about the reaction? A- It is a Brønsted-Lowry acid-base reaction, because the solution is neutral at the end. B- It is a Brønsted-Lowry acid-base reaction, because HNO 3(aq) is a strong acid. C- It is a redox reaction, because Cu(s) is oxidized and H +(aq) is reduced. D- It is a redox reaction, because Cu(s) is oxidized and the nitrogen atom in NO3−(aq) is reduced. Intermolecular Forces © 2015 Pearson Education, Inc.  Agenda Day 7 - Types of Rxns Lab Intermolecular Forces © 2015 Pearson Education, Inc. Types of Chemical Reactions Lab 5 minutes at each station. Only complete observations section- the rest you will do at the end of the block. DO NOT PUT ANYTHING IN THE SINK. Clean your station before moving clockwise to the next station. When you are finished, start the predicting products section of the lab at your seat. Note: This lab is good review for the quiz, the more you finish in class- the better. Intermolecular Forces © 2015 Pearson Education, Inc.