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Instructor Lesson Plan – (PIB/HH Chemistry) Unit 6: Chemical Reactions Instructor: Ditkowsky Introductory Resources: Addison-Wesley v.5 - Chapter 8 Addison-Wesley v.4 - Chapter 7 Advanced Resources: Brown v.4 - Chapter 3 Zumdahl v.3 - Chapter 3 Zumdahl v.5 - Chapter 3 Main Idea Summary: A chemical reaction can be concisely represented by a chemical equation. The substances that undergo a chemical reaction are the reactants. The new substances formed are the products. Special symbols are written after formulas in equations to show a substance’s state. The designations for solid, liquid, or gas, are (s), (l), and (g), respectively. A substance dissolved in water is designated (aq). A catalyst is a substance that increases reaction rate without being used up by the reaction. If a catalyst is used, its formula is written above the arrow. In accordance with the law of conservation of mass, a chemical equation must be balanced. In balancing an equation, coefficients are used so the same number of atoms of each element are on each side of the equation. In a synthesis reaction, there is always a single product. A decomposition reaction involves the breakdown of a single reactant. In a single replacement reaction, the reactants and products are an element and a compound. The activity series of metals can be used to predict whether single replacement reactions will take place. A double replacement reaction involves the exchange of cations between two compounds. This reaction generally takes place between two ionic compounds in aqueous solution. The solubility rules can be used to predict whether double replacement reactions will take place, and what product will be insoluble in water. A combustion reaction always involves oxygen. The products of the complete combustion of a hydrocarbon are carbon dioxide and water. A complete ionic equation shows all dissolved ionic compounds as their free ions. A netionic equation shows only the ions that take part in the actual reaction, and not the spectator ions, ions that do not participate in the reaction. HW6A: Outline Chapter 8. Add notes from the supplementary text below. Supplementary Text: A chemical reaction is the process by which one or more substances are changed into one or more different substances. The original substances are called REACTANTS and the resulting substances are called PRODUCTS. According to the Law of CONSERVATION OF MASS, the total mass of the reactants are equal to the total mass of the products. A chemical EQUATION represents with symbols and formulas, the identities and relative amounts of reactants and products in a chemical reaction. The following are indications of a chemical reaction: 1. Evolution of heat and light. A change in matter that releases energy as both heat and light is strong evidence that a chemical reaction has occurred. However, some physical changes also release either heat or light. 2. Production of a gas. The evolution of gas bubbles when two substances are mixed is often evidence of a chemical reaction. 3. Formation of a precipitate. Many chemical reactions take place between aqueous substances. If a solid appears after two solutions are mixed, a reaction has likely occurred. The solid in this case is called a PRECIPITATE. Characteristics of Chemical Equations. 1. The equation must represent known facts. 2. The equation must contain the correct formulas for the reactants and products. 3. The law of conservation of mass must be satisfied. Atoms are neither created nor destroyed in ordinary chemical reactions. To equalize numbers of atoms coefficients are added when necessary. COEFFICIENTS are small whole number ratios that appear in front of a formula in a chemical equation. Word and Formula Equations It is often helpful to begin with a word equation which describes the reactants and products. This qualitative description helps you to write a formula equation. A word equation has the general format of reactant product; where the means yield, reacs to formt, or forms. A formula equation represents the reactants and products of a chemical reaction using symbols/formulas. Once a formula equation is written, it can be balanced by adjusting the coefficients. Word Equation: Solid carbon reacts with steam to make carbon dioxide and hydrogen gas. Formula Equation: C(s) + H2O(g) CO2(g) + H2(g) Balanced Chemical Equation: 1 C(s) + 2 H2O(g) 1 CO2(g) + 2 H2(g) (Reactants: 1C, 4H, 2 O)(products 1C, 2 O, 4 H) matter is conserved! Types of Chemical Reactions There are five major types of reactions: 1. Composition or Synthesis 2. Decomposition 3. Single Replacement or Single Displacement 4. Double Replacement or Double Displacement or Metathesis 5. Combustion ____________________________________________________________________ Synthesis or Composition reactions have the general form A + B AB Examples of synthesis reactions include the addition of oxygen to another atom: ex: 2 Mg + O2 2 MgO S8 + 8 O2 8 SO2 4 Fe + 3 O2 2 Fe2O3 Both metals and nonmetals can combine with oxygen in synthesis reactions. Another type of synthesis reaction involves the reaction of metals with halogens. This is another type of reaction that can also occur with nonmetals. ex: 2 Na + Cl2 2 NaCl U + 3 F2 UF6 Ca + Cl2 CaCl2 O2 + F2 OF2 In both cases above, two elements are combining. It is also possible for two compounds to combine, or a compound and an element. ex: CaO + H2O Ca(OH)2 SO2 + H2O H2SO3 2 H2SO3+ O2 2 H2SO4 CaO + SO2 CaSO3 ___________________________________________________________________ Decomposition reactions have the general form AB A + B The simplest type of decomposition reaction involves a binary compound (bi = two) decomposing to its elements: ex: 2 H2O 2 H2 + O2 (electrolysis) 2 NaCl 2 Na + Cl2 (also done using electrolysis) 2 HgO 2 Hg + O2 CaS Ca + S There are patterns of decomposition reactions which make it very easy to predict what products you will get in a given decomposition reaction. Substances which are low energy are formed often, for example, water and carbon dioxide are frequently products of chemical reactions. Decomposition of Carbonates: MnCO3 Carbonates decompose to form the metal oxide and carbon dioxide. ex: CaCO3 CaO + CO2 Na2CO3 Na2O + CO2 Decomposition of Metal Hydroxides: Mn(OH)m Metal hydroxides decompose to form metal oxides and water. ex: Ca(OH)2 CaO + H2O 2 NaOH Na2O + H2O Decomposition of Metal Chlorates: Mn(ClO3)m Metal chlorates decompose to form chorides and oxygen. ex: Ca(ClO3)2 CaCl2 + 3 O2 2 NaClO3 2 NaCl + 3 O2 Decomposition of Acids: HXOn Certain acids decompose into nonmetal oxides and water. (Carbonic Acid decomposes like both an acid and a carbonate) ex: H2CO3 CO2 + H2O H2SO4 SO3 + H2O _________________________________________________________________ Single Replacement Reactions have the general form A + BC AC + B or A + BC BA + C In this type of reaction, the more active element can replace a less active element in a compound. This reaction is what I call the “home-wrecker reaction” because, we start with an element (a single) and a compound (a married couple). When the reaction is complete, the “marriage” has been broken up, and a new married couple and a newly (divorced) single exist. ex: 2 K + H2O 2 KOH + H2 Mr. Potassium meets Mr. and Mrs. Hydrogen-hydroxide (water). Hydrogen gets jealous and walks out. Mr. Potassium consoles Ms. Hydroxide and they marry. There are a few specific subcategories which may help you remember what to do for this type of prediction. Replacement of a metal in a compound by another metal ex: 2 Al + 3 Pb(NO3)2 3 Pb + 2 Al(NO3)3 Replacement of hydrogen in water by another metal ex: 2 Na + 2 H2O → 2 NaOH + H2 3 Fe + 4 H2O → Fe3O2 + 4 H2 Replacement of Hydrogen in an Acid by a Metal ex: Mg + 2 HCl → H2 + MgCl2 Replacement of Halogens ex: Cl2 + 2 KBr → 2 KCl + Br2 F2 + 2 NaCl → 2 NaF + Cl2 Note that in this case, since it is the anion which is being replaced, it is always placed second in the formula. To tell whether a reaction will occur, you must consult the activity series. Activity of metals Activity of Halogen nonmetals Li (most active) F2 Rb Cl2 K Br2 Ba I2 Sr Ca Na Above this line, these react with cold water replacing hydrogen. They also react spontaneously with elemental oxygen to produce oxides. Mg Al Mn Zn Cr Fe Cd Above this line, these react with steam (not cold water) and acids, replacing hydrogen. These react with oxygen, forming oxides. Co Ni Sn Pb Above this line, these do not react with water, they react with acids, replacing hydrogen. These react with oxygen forming oxides. H2 Sb Bi Cu Hg Above this line, these can react with oxygen to form oxides. Ag Pt Au Double Replacement Reactions have the general form AX + BY → AY + BX A and B represent metals (cations). X and Y represent nonmetals or polyatomic cations. I like to call this reaction the Prom Date reaction. A couple goes to prom and argue. At the end of the evening the couple separates. Two couples leave with each other’s date. If two people who went to prom together dance with each other’s date at prom, that is within acceptable behavior. Only when the couples break apart during the evening and remain broken up when Prom is over, only then do we consider that a reaction occurs. Just as it is accepted that during prom, individuals mingle and have a good time; in solution, the ions in a double replacement reaction float around in water, briefly interacting with other ions. When the reaction forms a precipitate, those ions are effectively removed from the solution. Reactions occur when collisions occur, solids are tethered, and can’t collide with enough force to react. (Like when two individuals pair up and spend the rest of the evening gazing soulfully into each other’s eyes and don’t notice the rest of the crowd). Another type of successful double replacement reaction occurs when a gas is formed. Since the gas is a vapor, those molecules are removed from the reaction. Formation of a Precipitate: ex: 2 KI (aq) + Pb(NO3)2 (aq) → PbI2 (s) + 2 KNO3 (aq) In this reaction, K+, I-, Pb2+ and NO31- are in aqueous solution. When they mix, the Pb2+and I1stick together to form solid PbI2. The solid PbI2 falls to the bottom of the solution and remains there. The K+ and NO31- continue to have collisions and break apart. Formation of a Gas: ex: FeS (s) + 2 HCl (aq) → H2S (g) + FeCl2 (aq) Formation of Water: ex: HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l) This type of reaction is also called a neutralization reaction, or an acid-base reaction. When an acid reacts with a base, the products are a salt (cation-anion) and water. Combustion Reaction When a hydrocarbon reacts with water, lots of heat is generated along with carbon dioxide and water. This is the process our body uses to process sugars, fats and carbohydrates. Our body uses enzymes to control the reactions so we can use the energy generated. In most combustion reactions, in addition to heat, light is also produced. Combustion requires an initial input of energy. Enzymes reduce the initial amount of energy and slow the reaction so we can use the energy to power our bodies. In the case of hydrocarbons in cars or gas stoves, the gas doesn’t ignite until a spark is applied to the gas vapor. Once ignited, boatloads of energy are given off in the form of heat and light. ex: 2 H2 + O2 → 2 H2O C3H8 + O2 → 3 CO2 + 4 H2O Worksheet 6.1 – Variety NAME _______________________ Put numbers in the blanks to balance the following equations. Learn to recognize the distinguishing features of each reaction type. SYNTHESIS (also known as COMBINATION): ___S + ___O2 → ___SO2 ___S + ___O2 → ___SO3 ___P + ___O2 → ___P2O5 DECOMPOSITION: ___KClO3 → ___KCl + ___O2 ___H2O2 → ___H2O + ___O2 ___NaNO3 → ___NaNO2 + ___O2 SINGLE REPLACEMENT (also known as DISPLACEMENT): ___Na + ___H2O → ___NaOH + ___H2 ___Zn + ___NaOH → ___Na2ZnO2 + ___H2 ___Zn + ___HCl → ___ZnCl2 + ___H2 DOUBLE REPLACEMENT (also known as METATHESIS): ___Fe(OH)3 + ___H2SO4 → ___Fe2(SO4)3 + ___H2O ___MgCl2 + ___NaOH → ___Mg(OH)2 + ___NaCl ___AgNO3 + ___H2S → ___Ag2S + ___HNO3 COMBUSTION: ___C3H8 + ___O2 → ___CO2 + ___H2O ___C6H14 + ___O2 → ___CO2 + ___H2O ___C9H20 + ___O2 → ___CO2 + ___H2O Laboratory Activity 6A – Synthesis 1. Wear Goggles 2. Observe a strip of magnesium ribbon. Write down any and all observed physical properties. 3. Use the sparklighter to ignite the Bunsen burner. 4. Use the crucible tongs to hold the magnesium ribbon in the Bunsen burner flame. Caution: DO NOT look directly at the chemical reaction, because it may cause damage to your eyes and permanently harm your vision. Remove the magnesium from the flame. 5. When the magnesium oxide has cooled, observe its properties. 6. Clean up your equipment and return it to your teacher. 7. Write a balanced equation explaining what happened in lab, causing the transformation of magnesium into magnesium oxide. Laboratory Activity 6B – Decomposition 1. Wear Goggles. 2. Put a small quantity of copper (II) sulfate pentahydrate into a crucible. Record the appearance of the substance. 3. Place the crucible on a wire triangle on a ring-stand with the cap balanced above the crucible (so hot air can escape). 4. Place the Bunsen burner below the crucible and use an igniter to light the burner. 5. Record observations. Do you see an moisture forming? Is the color changing? 6. Allow the crucible to cool before removing it with metal tongs. 7. Clean all equipment and return it to the cart. Data: Reactant (observations) A. B. During the reaction (observations) Products (observations Conclusions for Reactions A and B: Write a paragraph explaining what happened in the experiment and how you know that this happened. Make sure that your paragraph includes two balanced chemical equations. Using worksheet 6.1, write a procedure for a similar experiment. State Goals/Benchmark/Standard: 11A.4a-c, 13A.4a, 12C.4a, 12D.4b Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY TWO: Laboratory Activity 8A, Laboratory Activity 8B Students will perform these extremely simple experiments. The first experiment uses Bunsen burners to combine oxygen and magnesium in a synthesis reaction to form magnesium oxide. The second reaction will use a battery to conduct a decomposition reaction. Important ideas to consider are that energy must be provided to conduct a decomposition reaction, the idea here that decomposition is always endothermic. Also, students should be able to generate balanced reaction equations for this simple reaction. Students should become adept at identifying and master the balancing of Synthesis and Decomposition Reactions. Synthesis reactions are reactions in which two reactants yield one product. Decomposition reactions are endothermic reactions in which one reactant yields two products. General Case: Synthesis: Decomposition: A + B AB AB A + B ASSIGNMENT: Worksheet 6.2 Worksheet 6.2 – Synthesis and Decomposition NAME _______________________ Put numbers in the blanks to balance the following equations. Learn to recognize the distinguishing features of each reaction type. Write the word equation below each reaction. SYNTHESIS (also known as COMBINATION): 1. ___Ca + ___N2 → ___Ca3N2 Word equation: ____ moles Calcium react with ____ moles of nitrogen to form ___ moles of calcium nitride. 2. ___N2 + ___O2 → ___NO2 Word equation: 3. ___Cu + ___S → ___Cu2S Word equation: 4. ___Na + ___O2 → ___Na2O Word equation: 5. ___Al + ___N2 → ___AlN Word equation: 6. ___Hg + ___I2 → ___HgI2 Word equation: 7. ___Fe + ___O2 → ___Fe2O3 Word equation: 8. ___NO + ___O2 → ___NO2 Word equation: 9. ___H2 + ___Cl2 → ___HCl Worksheet 6.2 continued: DECOMPOSITION: 10. ___HgO → ___Hg + ___O2 Word equation: ____ moles of mercury (II) oxide decompose to form ____ moles of mercury and ___ moles of oxygen. 11. ___CaCO3 → ___CaO + ___CO2 Word equation: 12. ___CuSO4∙5H2O → ___CuSO4 + ___H2O Word equation: 13. ___NH4NO3 → ___N2O + ___H2O Word equation: 14. ___BaO2 → ___BaO + ___O2 Word equation: 15. ___NO2 → ___N2 + ___O2 Word equation: 16. ___H2O → ___H2 + ___O2 Word equation: 17. ___NH3 → ___N2 + ___H2 Word equation: 18. ___NCl3 → ___N2 + ___Cl2 Word equation: State Goals/Benchmark/Standard: 12C.4b, 12D.4b Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY THREE: Activity Series, Practice with Single Replacement Equations Students must learn about Single Replacement reactions. In a single replacement reaction, the atoms of an element replace the atoms of a second element in a compound. Metals replace metals. Nonmetals replace nonmetals. DEMONSTRATION: Sodium in Water The teacher will drop a small piece of sodium into a plastic container filled with water. This demonstration MUST be done in the fume hood. The sodium replaces the hydrogen in water, yielding hydrogen gas and sodium hydroxide. Students should be told that for the purposes of Single Replacement and Double Replacement, it might help them if they view water as a hydrogen ion bonded to a hydroxide ion, or HOH, instead of H2O. Whether one metal will replace another metal from a compound can be determined by the relative reactivity of the two metals. The Activity Series lists metals in order of decreasing reactivity. A reactive solo metal will replace any bonded metal found below it in the activity series. By contrast, a solo metal of lesser reactivity will not replace a bonded metal found above it in the table. Students must not only learn to balance single replacement reactions, but must also factor reactivity into any single replacement reactions they encounter, noting whether or not a single replacement reaction will occur. General Case: Single Replacement: AX + B BX + A Students are also taught of the memory aid, HONClBrIF, the list of diatomic elements. Most other elements are monatomic in nature. This fact will help students later on, when they are attempting to predict the products of a reaction, knowing only the reactants. ASSIGNMENT: Worksheet 6.3 Prepare Laboratory Activity 6C for use in class Activity Series of Metals: Lithium (highest reactivity) Cesium Rubidium Potassium Barium Strontium Calcium Sodium Magnesium Aluminum Manganese Zinc Chromium Iron Cadmium Cobalt Nickel Tin Lead Hydrogen Copper Silver Mercury Platinum Gold (lowest reactivity) Metals from Lithium to Sodium will replace Hydrogen from acids and water; from Magnesium to Lead they will replace Hydrogen from acids only. Activity Series of Halogens: F2 Cl2 Br2 I2 (highest reactivity) (lowest reactivity) Laboratory Activity 6C – Single Replacement 1. Wear Goggles. 2. Place a test tube in the test tube rack and fill it one third of the way up with 6 M Hydrochloric acid (WARNING: Hydrochloric acid is very caustic! If you get any on you, wash it off immediately and tell the teacher). 3. Drop the strip of Magnesium into the acid. Observe what happens. Record your observations. 4. Cover the mouth of the test tube with the second test tube to capture any gas that is produced in the tube. 5. Use a lit match to test the gas for flammability by putting it in the mouth of the inverted tube. 6. Rinse all glassware thoroughly before returning it. 7. Write a balanced equation for the reaction of magnesium metal with hydrochloric acid. Remember to include symbols after each chemical formula to represent the phase of each reactant and product. Step 5 of the lab should give a hint as to the identity of one of the products. Worksheet 6.3 – Single Replacement Put numbers in the blanks to balance the following equations. Use the Activity Series to answer the question at the right. (more reactive replaces less reactive in compounds.) SINGLE REPLACEMENT (also known as DISPLACEMENT): REACTION: WILL IT OCCUR? (Yes or No) 1. ___Fe2O3 + ___Cr → ___Cr2O3 + ___Fe ________ Word equation: 2. ___Al + ___CuSO4 → ___Al2(SO4)3 + ___Cu ________ Word equation: 3. ___Ca + ___LiNO3 → ___Li + ___Ca(NO3)2 ________ Word equation: 4. ___Cr + ___H2SO4 → ___Cr2(SO4)3 + ___H2 ________ Word equation: 5. ___Zn(NO3)2 + ___Ag → ___AgNO3 + ___Zn ________ Word equation: 6. ___MgCl2 + ___K → ___KCl + ___Mg ________ Word equation: 7. ___MgCl2 + ___Ag → ___AgCl + ___Mg ________ Word equation: 8. ___Cu + ___AgNO3 → ___Ag + ___Cu(NO3)2 ________ Word equation: 9. ___Mn + ___Pb(C2H3O2)4 → ___Pb + ___Mn(C2H3O2)2 ________ Word equation: 10. ___PtO2 + ___H2 → ___Pt + ___H2O Word equation: ________ Worksheet 6.3 continued: 11. ___Fe + ___CuSO4 → ___Cu + ___FeSO4 ________ Word equation: 12. ___Co + ___Ba(NO3)2 → ___Ba + ___Co(NO3)2 ________ Word equation: 13. ___Hg + ___Pt(OH)2 → ___Pt + ___Hg(OH)2 ________ Word equation: 14. ___Al(C2H3O2)3 + ___Mg → ___Al + ___Mg(C2H3O2)2 ________ Word equation: 15. ___Sr(NO3)2 + ___Na → ___NaNO3 + ___Sr ________ Word equation: 16. ___AlF3 + ___Cl2 → ___AlCl3 + ___F2 ________ Word equation: 17. ___HI + ___Br2 → ___HBr + ___I2 ________ Word equation: 18. ___Br2 + ___NaCl → ___NaBr + ___Cl2 ________ Word equation: 19. ___ Cl2 + ___ NaBr ___ NaCl + Word equation: ___ Br2 ________ State Goals/Benchmark/Standard: 12C.4a, 12D.4b, 11A.4a-e, 13A.4a Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY FOUR: Laboratory Activity 6C Students will complete the Single Replacement Laboratory in the time allotted. After the lab is done, the teacher should go over more single replacement reactions so that they are more adept at using the Reactivity Series to identify whether or not a reaction should occur. ASSIGNMENT: Worksheet 6.4 Worksheet 6.4 – Double Replacement I NAME _______________________ Put numbers in the blanks to balance the following equations. DOUBLE REPLACEMENT (also known as METATHESIS): REACTION: 1. ___Fe2O3 + ___AlP → ___Al2O3 + ___FeP Word equation: 2. ___NaCl + ___K2SO4 → ___Na2SO4 + ___KCl Word equation: 3. ___Pb(NO3)2 + ___BaCl2 → ___Ba(NO3)2 + ___PbCl2 Word equation: 4. ___Na3P + ___CaO → ___Na2O + ___Ca3P2 Word equation: 5. ___Al2O3 + ___AgCl → ___AlCl3 + ___Ag2O Word equation: 6. ___AgCl + ___PbS → ___PbCl2 + ___Ag2S Word equation: 7. ___Au2S3 + ___KCl → ___AuCl3 + ___K2S Word equation: 8. ___KOH + ___Al2S3 → ___Al(OH)3 + ___K2S Word equation: Worksheet 6.4 continued: 9. ___AuCl3 + ___H2O → ___HCl + ___Au(OH)3 Word equation: 10. ___AgNO3 + ___CuCl2 → ___AgCl + ___Cu(NO3)2 Word equation: 11. ___CaCO3 + ___HCl → ___CaCl2 + ___H2CO3 Word equation: 12. ___BaCl2 + ___(NH4)2CO3 → ___BaCO3 + ___NH4Cl Word equation: State Goals/Benchmark/Standard: 12C.4b, 12D.4b Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY FIVE: Solubility Rules, Practice with Double Replacement Reactions Double Replacement reactions occur when positive ions are exchanged between two ionically bonded compounds. The reaction generally takes place between two ionic compounds in aqueous solutions. General Case: Double Replacement: AX + BY BX + AY The ions disassemble in solution, rearrange, and reform, yielding either a precipitate, a gas, or a compound like water. Regarding the precipitate formation, one of the pairs of ions will form a solid compound in accordance with the rules of solubility. Students are to use the solubility rules in determining whether or not a Double Replacement actually occurs, whether a precipitate is forms, in addition to merely balancing the equations. It is the action of these ions, forming this solid, that drive the reaction. The other ions will do nothing, not being directly involved in the reaction. These ions are known as spectator ions. More will be made of this during the next day of class. Once again, students should be reminded that for Single and Double Replacement reactions, water should be viewed as HOH, and not H2O. Also, most polyatomic ions tend to stay together during Double Replacement reactions. The Double Replacement Laboratory Activity should be prepared for use in class. ASSIGNMENT: Worksheet 6.5 Prepare Laboratory Activity 6D for use in class Solubility Rules: Water-Soluble Salts: 1. All salts of the chloride ion, Cl-1, bromide ion, Br-1, and iodide ion, I-1, are soluble except those of Ag+1, Hg2+2, Pb+2, Cu+1, and Tl+1. BiI3 and SnI4 are insoluble. PbCl2 is three to five times more soluble in hot water than in cold water. 2. All salts of the acetate ion CH3CO2-1, nitrate ion, NO3-1, chlorate ion, ClO3-1, perchlorate ion, ClO4-1, and permanganate ion, MnO4-1, are soluble. 3. All common salts of the Group 1A cations and ammonium ion, NH4+1, are soluble. 4. All common salts of the sulfate ion, SO4-2, are soluble except those of Ba+2, Sr+2, Pb+2, and Hg+2. 5. All Group 1A and 2A salts of the bicarbonate ion, HCO3-1, are soluble. 6. Most salts of the fluorosilicate ion, SiF6-2, thiocyanate ion, SCN-1, and thiosulfate ion, S2O3-2, are soluble. Exceptions are the Ba+2 and Group 1A fluorosilicates, the Ag+1, Hg2+2, and Pb+2 thiocyanates, and the Ag+1 and Pb+2 thiosulfates. Water-Insoluble Salts: 1. All common salts of the fluoride ion, F-1, are insoluble except those of Ag+1, NH4+1, and Group 1A cations. 2. In general, all common salts of the carbonate ion, CO3-2, phosphate ion, PO4-3, borate ion, BO3-3, arsenate ion, AsO4-3, arsenite ion, AsO3-3, cyanide ion, CN-1, ferricyanide ion, [Fe(CN)6]-3, ferrocyanide ion, [Fe(CN)6]-4, oxalate ion C2O4-2, and the sulfite ion, SO3-2, are insoluble, except those of NH4+1 and the Group 1A cations. 3. All common salts of the oxide ion, O-2, and the hydroxide ion, OH-1, are insoluble except those of the Group 1A cations, Ba+2, Sr+2, and NH4+1. Ca(OH)2 is slightly soluble. Soluble oxides produce the corresponding hydroxides in water. 4. All common salts of the sulfide ion, S-2, are insoluble except those of NH4+1 and the cations that are isoelectronic with a noble gas. 5. Most common salts of the chromate ion, CrO4-2, are insoluble except those of NH4+1, Ca+2, Cu+2, Mg+2, and the Group 1A cations. 6. All common salts of the silicate ion, SiO3-2 are insoluble except those of the Group 1A cations. Worksheet 6.5 – Double Replacement II NAME _______________________ Put numbers in the blanks to balance the following equations. Using the Solubility Rules and a highlighter, mark which ions typically form a precipitate. Then, predict whether or not an insoluble product will be formed, and identify the predicted solid precipitate (or if none, the words “no reaction”) in the blank at the right. DOUBLE REPLACEMENT (also known as METATHESIS): REACTION: 1. ___Pb(NO3)2 + _2_NaBr → _2_NaNO3 + ___PbBr2 ________ Word equation: one mole of aqueous lead (II) nitrate reacts with 2 moles of aqueous sodium bromide to form two moles of aqueous sodium nitrate and one mole of lead (II) bromide precipitate. 2. ___AgHCO3 + ___NaCl → ___NaHCO3 + ___AgCl ________ Word equation: 3. ___K2SO4 + ___BaCl2 → ___BaSO4 + ___KCl ________ Word equation: 4. ___Ba(NO3)2 + ___Li2SiF6 → ___BaSiF6 + ___LiNO3 ________ Word equation: 5. ___AgF + ___Ca(NO3)2 → ___AgNO3 + ___CaF2 ________ Word equation: 6. ___(NH4)2CrO4 + ___Fe(NO3)3 → ___NH4NO3 + ___Fe2(CrO4)3 ________ Word equation: 7. ___AgMnO4 + ___KCl → ___AgCl + ___KMnO4 Word equation: ________ Worksheet 6.5 continued: 8. ___KOH + ___Al2(SO4)3 → ___Al(OH)3 + ___K2SO4 ________ Word equation: 9. ___(NH4)2S + ___SrO → ___(NH4)2O + ___SrS ________ Word equation: 10. ___AgClO4 + ___NaSCN → ___AgSCN + ___NaClO4 ________ Word equation: 11. ___Na2CO3 + ___BaCl2 → ___NaCl + ___BaCO3 Word equation: ________ Laboratory Activity 6D – Double Replacement 1. Wear Goggles. 2. Observe a solution of Lead (II) Nitrate, Pb(NO3)2. 3. Fill a test tube about 1/3 of the way up with Pb(NO3)2. 4. Observe a solution of Barium Chloride, BaCl2. 5. Add an equal amount of BaCl2 to the tube. 6. Record your observations of what occurs in the tube for the next several minutes. 7. Write out a balanced equation for what occurs in the tube. Predict the identity of the precipitate. 8. Clean up your station. Discard the contents of the tube in the solution waste container provided by the teacher. State Goals/Benchmark/Standard: 12C.4b, 12D.4b Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY SIX: Ionic Equations, Net Ionic Equations, Spectator Ions The Double Replacement Reaction is driven by a precipitate formation. Two different solutions of aqueous ions are used as reactants. Each of the aqueous solutions dissociates into ions. Then, positive ions are exchanged, and new compounds are formed. In accordance with the solubility rules, if one of the products formed is a solid, a precipitate is formed. If not, no reaction occurs. Students must be taught how to correctly write out a Double Replacement reaction. There are three ways to write the equation out. The overall equation must be written out with subscripts designating the phase of each species involved. (aq) stands for aqueous, meaning that the compound in question breaks up into ions upon being put into water. (s) stands for solid, the phase of the precipitate. (l) stands for pure liquids that might be formed, as in products such as water. (g) stands for gas, which escapes from the reaction vessel. The ionic equation contains all of the ions involved in the reaction, and correctly identifies the precipitate with a designation of (s). This includes two ions which are not required for the formation of the precipitate. Since these ions are not involved in the actual precipitate formation, they are known as spectator ions. The net-ionic equation is similar to the ionic equation, except without the inclusion of the spectator ions. Students must be able to write out each of these types of equations for each of the Double Replacement Reactions they encounter. The teacher should spend the rest of the class period helping the students understand these equation writing techniques by rewriting the equations from Balancing Equations Worksheet #06 in all three ways. ASSIGNMENT: Rewrite equations from Worksheet 6.5 as “overall equations,” “ionic equations,” and “net-ionic equations.” Worksheet 6.6 Worksheet 6.6 – Double Replacement III NAME _______________________ Put numbers in the blanks to balance the following equations. Using the Solubility Rules, rewrite the equations as overall equations, ionic equations, and net-ionic equations. Be sure to include identification of phases, like (s), (l), (g), or (aq) in the reactions. DOUBLE REPLACEMENT (also known as METATHESIS): REACTION: 1. ___CaCl2 + ___K2CO3 → ___CaCO3 + ___KCl Overall Equation: Ionic Equation: Net-Ionic Equation: 2. ___AgNO3 + ___FeCl3 → ___AgCl + ___Fe(NO3)3 Overall Equation: Ionic Equation: Net-Ionic Equation: 3. ___Al(OH)3 + ___HC2H3O2 → ___Al(C2H3O2)3 + ___H2O Overall Equation: Ionic Equation: Net-Ionic Equation: 4. ___NaNO3 + ___K2SO3 → No Reaction (Answer the following to demonstrate why) Overall Equation: Ionic Equation: Net-Ionic Equation: State Goals/Benchmark/Standard: 12C.4b, 12D.4b, 14A.4a-e, 13A.4a Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY SEVEN: Double Replacement Laboratory Students will complete the laboratory activity during the class period. During any leftover time, students should continue their work with Double Replacement Reactions. ASSIGNMENT: Worksheet 6.7 Prepare Laboratory Activity 6E for use in class Laboratory Activity 6E – Combustion 1. Wear Goggles. 2. Use a dropper pipet to transfer 10 drops of Ethanol into a watch glass. 3. Drop a lit match into the watch glass and observe the flame. 4. Smother the flame by covering it with an inverted plastic cup. Observe the sides of the cup. What compound builds up on the sides of the cup? 5. Wash and dry the glassware you used. 6. Ethanol has a formula of CH3CH2OH. Write a balanced equation for the combustion of ethanol. Worksheet 6.7 – Double Replacement IV Put numbers in the blanks to balance the following equations. Using the Solubility Rules, rewrite the equations as overall equations, ionic equations, and net-ionic equations. Be sure to include identification of phases, like (s), (l), (g), or (aq) in the reactions. REACTION: 1. ___Na2SO4 + ___Ba(NO3)2 → ___NaNO3 + ___BaSO4 Overall Equation: Ionic Equation: Net-Ionic Equation: 2. ___CuHCO3 + ___KBr → ___CuBr + ___KHCO3 Overall Equation: Ionic Equation: Net-Ionic Equation: 3. ___MgCrO4 + ___BaI2 → ___MgI2 + ___BaCrO4 Overall Equation: Ionic Equation: Net-Ionic Equation: 4. ___NH4CN + ___Fe(NO3)3 → ___NH4NO3 + ___Fe(CN)3 Overall Equation: Ionic Equation: Net-Ionic Equation: State Goals/Benchmark/Standard: 12C.4b, 12D.4b Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY EIGHT: Combustion Reactions Students should be introduced to the balancing of Combustion Equations. Combustion reactions involve the combination of a hydrocarbon, a chemical composed primarily of carbons and hydrogens, with oxygen gas to yield carbon dioxide and water. General Case: Combustion: CxHy + O2 CO2 + H2O The best way to approach a Combustion equation is to begin by balancing Carbon. Then, Hydrogen should be balanced next. Oxygen should be saved for last because it appears in so many places in the reaction. ASSIGNMENT: Worksheet 6.8 Worksheet 6.8 – Combustion NAME _______________________ Put numbers in the blanks to balance the following equations. Name the hydrocarbon where indicated, you may have to draw the Lewis structure first. COMBUSTION: REACTION: ___C3H8 + ___O2 → ___CO2 + ___H2O C3H8 = ___________________ ___C4H10 + ___O2 → ___CO2 + ___H2O C4H10= ___________________ ___C5H12 + ___O2 → ___CO2 + ___H2O ___C7H16 + ___O2 → ___CO2 + ___H2O ___C7H14 + ___O2 → ___CO2 + ___H2O ___C9H20 + ___O2 → ___CO2 + ___H2O ___C6H14 + ___O2 → ___CO2 + ___H2O ____CH4 + ___O2 → ___CO2 + ___H2O CH4 = ____________________ ___C2H2 + ___O2 → ___CO2 + ___H2O C2H2 = ___________________ ___C2H4 + ___O2 → ___CO2 + ___H2O C2H4 = ___________________ ___C2H6 + ___O2 → ___CO2 + ___H2O ___C8H18 + ___O2 → ___CO2 + ___H2O ___C6H6 + ___O2 → ___CO2 + ___H2O ___C6H12 + ___O2 → ___CO2 + ___H2O ___C6H12O6 + ___O2 → ___CO2 + ___H2O ___C12H22O11 + ___O2 → ___CO2 + ___H2O ___C8H16 + ___O2 → ___CO2 + ___H2O ___C85H172 + ___O2 → ___CO2 + ___H2O State Goals/Benchmark/Standard: 12C.4b, 12D.4b, 11A.4a-e, 13A.4a Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY NINE: Combustion Laboratory Activity Students will perform the Combustion Laboratory Activity during class. If time permits, students will do further work with identifying and balancing Combustion Equations. ASSIGNMENT: Worksheet 6.9 Worksheet 6.9 – Ridiculous Combustion NAME _______________________ Put numbers in the blanks to balance the following equations. COMBUSTION: REACTION: ___C35H72 + ___O2 → ___CO2 + ___H2O ___C412H826 + ___O2 → ___CO2 + ___H2O ___C50H102 + ___O2 → ___CO2 + ___H2O ___C50H100 + ___O2 → ___CO2 + ___H2O ___C5H11OH + ___O2 → ___CO2 + ___H2O ___C8H15OH + ___O2 → ___CO2 + ___H2O ___C6000H12002 + ___O2 → ___CO2 + ___H2O ___CH3OH + ___O2 → ___CO2 + ___H2O ___HC2H3O2 + ___O2 → ___CO2 + ___H2O ___C26H54 + ___O2 → ___CO2 + ___H2O ___CH3CH2OH + ___O2 → ___CO2 + ___H2O ___C6H5COOH + ___O2 → ___CO2 + ___H2O State Goals/Benchmark/Standard: 12C.4b, 12D.4b Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY TEN: Prediction Equations The teacher will instruct students as to how to predict the products of chemical reactions. Students will use the General Case scenarios to predict the outcome of equations. General Case: Synthesis: Decomposition: Single Replacement: Double Replacement: Combustion: A + B → AB AB → A + B AX + B → BX + A AX + BY → BX + AY CxHy + O2 → CO2 + H2O The teacher will work through the first worksheet with the students. The students will work the second worksheet for homework. ASSIGNMENT: Worksheet 5.10 Worksheet 5.11 Prepare Laboratory Activity 5F for use in the class Worksheet 6.10 – Basic Predictions NAME _______________________ Use the General Cases to predict the products of each reaction. Balance each equation when done. Identify each reaction type in the blank at the right. General Case: Synthesis: Decomposition: Single Replacement: Double Replacement: Combustion: A + B → AB AB → A + B AX + B → BX + A AX + BY → BX + AY CxHy + O2 → CO2 + H2O REACTION: ___C5H12 + ___O2 → _________________ ___Zn + ___HCl → _________________ ___Na2O → _________________ ___Li + ___Cl2 → _________________ ___Na2SO4 + ___LiCl → _________________ ___C4H10 + ___O2 → _________________ ___Al2O3 → _________________ ___Al + ___I2 → _________________ ___Zn(OH)2 + ___Al2(CO3)3 → _________________ ___FeCl3 → _________________ Worksheet 6.11 – More Predictions NAME _______________________ Use the General Cases to predict the products of each reaction. Balance each equation when done. Identify each reaction type in the blank at the right. General Case: Synthesis: Decomposition: Single Replacement: Double Replacement: Combustion: A + B → AB AB → A + B AX + B → BX + A AX + BY → BX + AY CxHy + O2 → CO2 + H2O REACTION: ___CuCl2 + ___Na3PO4 → _________________ ___C12H26 + ___O2 → _________________ ___FeCl3 → _________________ ___K2SO4 + ___Li → _________________ ___Na + ___O2 → _________________ ___C3H8 + ___O2 → _________________ ___KMnO4 + ___Li → _________________ ___Na3P + ___Ba(OH)2 → _________________ ___H2O → _________________ ___HCl + ___Ca(OH)2 → _________________ Laboratory Activity 6F – Predict The Products You will react nine different chemicals together in double replacement reactions. Some of the chemicals will react, producing a precipitate; some will not. You must use the Solubility Rules to determine beforehand which reactions should occur and which should not. The experiment will be used to verify your predictions. You will react each of the following chemicals in every possible combination: Lead (II) Nitrate Magnesium Sulfate Copper (II) Chloride Sodium Chloride Sodium Carbonate Potassium Hydroxide Barium Chloride Calcium Acetate Copper (II) Sulfate CuSO4 KOH CuCl2 Ca(C2H3O2)2 Na2CO3 MgSO4 BaCl2 NaCl Pb(NO3)2 The following matrix is designed to help you keep track of the reactions. Use one drop of each reagent in a well plate. If the results are inconclusive with only one drop, use more. Pb(NO3)2 X NaCl X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X BaCl2 MgSO4 Na2CO3 Ca(C2H3O2)2 CuCl2 KOH CuSO4 X State Goals/Benchmark/Standard: 12C.4b, 12D.4b Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY ELEVEN: Practice with Prediction Equations Students will continue their work on Prediction Equations in class, with the aid of the teacher. More problems and worksheets will be assigned. ASSIGNMENT: Worksheet 5.12 Worksheet 5.13 Worksheet 6.12 – Still More Predictions NAME _______________________ Predict the products of each reaction. Balance each equation when done. Identify each reaction type in the blank at the right. REACTION: ___Mg + ___O2 → _________________ ___AlCl3 → _________________ ___Na + ___O2 → _________________ ___HCl + ___NaOH → _________________ ___Pb(SO4)2 + ___Al(C2H3O2)3 → _________________ ___C4H10 + ___O2 → _________________ ___H3PO4 + ___MgCO3 → _________________ ___HgCl2 + ___NaSCN → _________________ ___PtO2 + ___H2 → _________________ ___CaCO3 + ___NaCl → _________________ ___Ag + ___HNO3 → _________________ ___NCl3 → _________________ ___MgSO4∙7H2O → _________________ Worksheet 6.13 – Yet More Predictions NAME _______________________ Predict the products of each reaction. Balance each equation when done. Identify each reaction type in the blank at the right. REACTION: ___Sr + ___O2 → ________________ ___Na + ___H2O → ________________ ___Zn + ___HCl → ________________ ___ICl → ________________ ___Fe(OH)3 + ___H2SO4 → ________________ ___C6H14 + ___O2 → ________________ ___Au(OH)3 + ___Na2CO3 → ________________ ___SrCl2 + ___NaOH → ________________ ___OCl2 → ________________ ___AgNO3 + ___H2SO4 → ________________ ___Zn + ___O2 → ________________ ___Mg(OH)2 + ___NaF → ________________ ___C30H62 + ___O2 → ________________ ___Mg(NO3)2 + ___H2O → ________________ ___Au2S3 → ________________ ___Ti(MnO4)4 + ___Fe2O3 → ________________ ___MnF2 + ___O2 → ________________ ___CO2 → ________________ State Goals/Benchmark/Standard: 11A.4a-e, 13A.4a Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension DAY TWELVE: Laboratory Activity 5F Students should spend the period working on the Prediction Laboratory Activity. For each of the Double Replacement reactions that occurred, students should write out an Overall Equation and a Net Ionic Equation. This should be done on a separate sheet of paper, and turned in at the end of the lab period, if possible. If there is any time left over, the teacher should lead the class on a review of the unit. ASSIGNMENT: Laboratory Equations turned in at end of period, if possible State Goals/Benchmark/Standard: Performance Descriptor: Curriculum Reading Initiative: DAY THIRTEEN: Review Balancing Equations The teacher will lead students through a comprehensive review of the unit on Balancing Equations and Predicting Products. Any topics that are problematic should be reviewed one more time. ASSIGNMENT: Study for Unit Exam Worksheet 5.14 Worksheet 6.14 – One More Time NAME _______________________ Balance each equation when done. Identify each type of reaction in the blank at the right. a) ___Na + ___I2 → ___NaI ____________ b) ___H2CO3 → ___H2O + ___CO2 ____________ c) ___C3H8 + ___O2 → ___CO2 + ___H2O ____________ d) ___Na3PO4 + ___Zn → ___Na + ___Zn3(PO4)2 ____________ e) ___LiCl + ___Pb(NO3)2 → ___PbCl2 + ___LiNO3 ____________ f) ___MgSO4 + ___NaNO3 → ___Na2SO4 + ___Mg(NO3)2 ____________ Which of the above reactions requires energy to proceed? Two of the above reactions will not occur experimentally. Identify each one, and briefly explain why the reaction will not take place. Predict the products of the following reactions. Balance and identify the equations. ___C2H6 + ___O2 → ____________ ___H2 + ___Li → ____________ ___MgSO4 + ___K → ____________ ___KMnO4 + ___Al(OH)3 → ____________ ___MnI4 → ____________ What are the two possible ions that can be made from hydrogen atoms? Identify the following ions: SO4-2 __________ SO3-2 __________ HSO4-1 __________ IO3-1 __________ IO2-1 __________ HCO3-1 __________ State Goals/Benchmark/Standard: 11A.4a-e, 13A.4a Performance Descriptor: Stage I Curriculum Reading Initiative: Fluency, Comprehension, Writing DAY FOURTEEN: Exam Students have the entire period to complete the exam. ASSIGNMENT: Begin next unit NAME _______________________ Practice Exam – Balancing Equations: Balance each equation when done. a) ___K + ___Cl2 → ___ ____________ b) ___ CO2MgS + ___NaNO3 → ___Na2S + ___ ____________ c) ___C12H24 + ___O2 → ___CO2 + ___ __________ ____________ d) ___Sr3PO4 + ___Al → ___Sr + ___ ____________ e) ___NaC2H3O2 + ___Pb(NO3)4 → ___Pb(C2H3O2)4 + ___ ____________ f) ___ Fe2CO3 → ___Fe2O + ___ ___________ Predict the products of the following reactions. Balance and identify the equations. a) ___CH4 + ___O2 → ____________ b) ___MgSO4 + ___Sr → ____________ c) ___Au(MnO4)3 + ___Al(OH)3 → ____________ d) ___FeI3 → ____________ e) ___Au(SO3)3 + ___Pb(NO3)2 → ____________ Balance the following reactions by adding filling in the blanks. a) ___H3PO4 + ___Al(OH)3 → ___ _________ + ___H2O b) ___NH4NO3 → ___N2O + ___H2O c) ___NO2 + ___H2O → ___HNO3 + ___NO d) ___C12H22O11 + ___O2 → ___CO2 + ___H2O Circle every one of the following that would replace chromium ion in CrF2. Li Fe Ca Pt Mn Cs Pb Sr Cu Hg Rb Circle every one of the following that would form a precipitate with BaCl2. NaNO3 Pb(NO3)2 Na2SO4 LiHCO3 AgF K2SiO3 K NAME _______________________ Exam – Balancing Equations (Form B): Balance each equation when done. Identify each type of reaction in the blank at the right. a) ___N2 + ___Cl2 → ___NCl3 ____________ b) ___Na2O → ___Na + ___O2 ____________ c) ___C9H20 + ___O2 → ___CO2 + ___H2O ____________ d) ___Li2SO4 + ___Al → ___Li + ___Al2(SO4)3 ____________ e) ___Mg(C2H3O2)2 + ___Fe(NO3)3 → ___Fe(C2H3O2)3 + ___Mg(NO3)2 f) ___Fe2S3 → ___Fe + ___S8 ____________ ____________ Predict the products of the following reactions. Balance and identify the equations. a) ___Au2(SO4)3 + ___Mg(OH)2 → ____________ b) ___MgCO3 + ___Li → ____________ c) ___C6H6 + ___O2 → ____________ d) ___Mg3N2 → ____________ e) ___Al2(SO3)3 + ___Pb → ____________ Balance the following reactions by adding coefficients before reactants and products. a) ___H3PO4 + ___NaOH → ___Na3PO4 + ___H2O b) ___F + ___C + ___G → ___F2G2C c) ___PbO2 + ___H2O → ___PbH4 + ___O2 d) ___C102H200O51 + ___O2 → ___CO2 + ___H2O Circle every one of the following that would replace calcium ion in CaF2. Li Fe Pt Cs Pb Sr Cu Hg Rb K Mn Circle every one of the following that would form a precipitate with Sr(OH)2. Na2SO4 LiHCO3 Pb(NO3)2 AgF K2SiO3 NaNO3 Au NAME _______________________ Exam – Balancing Equations: Balance each equation when done. Identify each type of reaction in the blank at the right. a) ___Na + ___Cl2 → ___NaCl ____________ b) ___C10H22 + ___O2 → ___CO2 + ___H2O ____________ c) ___Na3PO4 + ___Al → ___Na + ___AlPO4 ____________ d) ___LiC2H3O2 + ___Pb(NO3)4 → ___Pb(C2H3O2)4 + ___LiNO3 ____________ Predict the products of the following reactions. Balance and identify the equations. a) ___CH4 + ___O2 → ____________ b) ___MgSO4 + ___Sr → ____________ c) ___FeI3 → ____________ d) ___Au(SO3)3 + ___Pb(NO3)2 → ____________ Balance the following reactions by adding coefficients before reactants and products. a) ___H3PO4 + ___Al(OH)3 → ___AlPO4 + ___H2O b) ___NH4NO3 → ___N2O + ___H2O c) ___NO2 + ___H2O → ___HNO3 + ___NO d) ___C12H22O11 + ___O2 → ___CO2 + ___H2O Circle every one of the following that would replace chromium ion in CrF2. Li Fe Ca Pt Mn Cs Circle every one of the following that would form a precipitate with BaCl2. NaNO3 Pb(NO3)2 Na2SO4 How many grams of BaCl2 are needed to make 75 mL of a 1.2 M solution?