Honors Chemistry - Unit 5 Chapter 8 Chemical Equations Quiz on Diatomic Molecules: Tues., Nov. 15th Test Date: Fri., Nov. 26th VOCABULARY Assignment Use the Two-column Notes format/strategy to study/complete your vocabulary assignment. chemical reaction reactants products single displacement double displacement decomposition synthesis combustion subscript coefficient activity series Unit 8 Packet - Page 1 of 18 OBJECTIVES: Be able to balance chemical equations using coefficients. Be able to identify and write the five basic types of equations: single displacement, double displacement, synthesis, decomposition and combustion. Be able to use correct notation in equations (such as state symbols). Be able to identify the seven diatomic molecules and use them correctly in equations. Be able to use the activity series to write equations SYMBOLS USED IN CHEMICAL EQUATIONS (brief descriptions and table listed below) State symbols (after formula) s, l, g or aq (book uses cr for crystalline solid) up arrow ( ) gas down arrow ( ) ppt reversible rxn squiggly line above arrow = electric current or with e - as shown below above arrow = heat temp, pressure may be written above arrow catalyst may be written below or above arrow Unit 5 PROBLEM SET Chemical Equations: Follow the instructions for the cover page for Problem Sets. Show your work on all problems. Credit will not be given without work. Include units on your answers. Review Questions: 1. Name the following: A. FeSO4 B. BaCl2 C. CO D. NH4NO2 2. Write the formula for the following: A. diphosphorus trisulfide B. cobalt (III) carbonate C. silver sulfide Unit 8 Packet - Page 2 of 18 3. Nicotine, a component of tobacco, is 74.1 percent C, 8.6 percent H and 17.3 percent N by mass; the molar mass is about 162.5 g. What is nicotine s empirical formula? Its molecular formula? 4. A. How many formula units in 78.3 g of lead (II) phosphate? B. Calculate the molarity of a 1.5 liter solution of 498.6 g of lead (II) phosphate. 5. Calculate the percent composition of aluminum dichromate. Current Unit Material: 6. Write balanced equations for the following reactions: A. Calcium metal is added to water. B. A solution of tin (II) chloride is added to a solution of iron (III) sulfate C. Chlorine gas is bubbled into a solution of lithium iodide. D. C3H8 is burned in oxygen 7. How is 2Cl different from Cl2? 8. Octane, C8H18, is a component of gasoline. Write the balanced equation for the complete combustion of octane. (extra credit) 9. The poisonous gas, hydrogen sulfide, can be neutralized with a base such as NaOH producing water and sodium sulfide. A student asked to write a balanced equation for the reaction wrote the following: Na2OH(aq) + H2S (g) Na2S (aq) + H2O (l) A. Is this equation correct? B. Explain why or why not, and supply the correctly balanced equation if necessary.
CHEMICAL EQUATIONS AND REACTIONS Chemical Equation: represents with symbols and formulas the reactants and products Example: Reactants yields Products Fe2O3 + 2 Al 2 Fe + Al2O3 Equations must: Represent known facts all reactants and products must be included Contain correct formulas Coefficients: numbers in front of compounds/elements Represents the number of moles Subscripts: numbers in the formulas They are never changed! Symbols used in equations are on your objective sheet! Unit 8 Packet - Page 3 of 18 Unit 8 Packet - Page 4 of 18 When writing equations you must satisfy the law of conservation matter (matter can not be created or destroyed) Therefore we must have the same type and number of each atom on each side of the equation. BALANCING EQUATIONS: 4 steps: 1. Start with a word equation 2. Convert to a formula equation (don t forget the diatomic molecules!) 3. Balance with coefficients: balance each atom one at a time balance polyatomic ions on each side of the equation as one unit balance H and O last (they often appear in more than one compound) 4. Check; if coefficients are not the lowest possible; reduce down. *****Remember NEVER change subscripts***** Examples: 1. water breaks down into hydrogen and oxygen WRITING AND BALANCING EQUATIONS Diatomic molecules: Occur in pairs in their natural state (when they are alone and not ionic, not in compounds) Notice there are 7 of these and they make a 7 shape on the PT!!!!! Memorize!! (quiz): 2. aluminum carbide reacts with water to produce methane gas (CH4) and aluminum hydroxide 3. Na2SO4 + LiCl Li2SO4 + NaCl Writing & Balancing Equations You try: 1. calcium oxide reacts with bromine to make calcium bromide and oxygen Diatomic molecules occur in pairs in their natural state (when they are alone; not in compounds) I 2, Br 2, Cl 2, F 2, O 2, N 2, H 2 (*Quiz*) I Bring Clay For Our New House or His Brown Clown Found No Oranges Inside 2. Ba(NO3)2 + PbO2 BaO + Pb(NO3)4
Unit 8 Packet - Page 5 of 18 Unit 8 Packet - Page 6 of 18
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BALANCING CHEMICAL REACTIONS Balance the following reactions: 1. K3PO4 + HCl KCl + H3PO4 2. Na + HNO3 NaNO3 + H2 3. S + O2 SO3 4. Ca(ClO3)2 CaCl2 + O2 5. C2H12 + O2 CO2 + H2O 6. Potassium iodide + lead (II) nitrate potassium nitrate + lead (II) iodide Unit 8 Packet - Page 9 of 18 Unit 8 Packet - Page 10 of 18 Equation Writing Balance and ID the following rxns: 1. Zn + H2SO4 ZnSO4 + H2 2. Na + Br2 NaBr 3. H2O H2 + O2 4. Cl2 + KI KCl + I2 5. HNO3 + LiOH H2O + LiNO3 6. C3H8 + O2 CO2 + H2O 7. Sodium + iodine sodium iodide 7. Iron (III) oxide + carbon carbon monoxide + iron 8. Mercury (II) oxide mercury + oxygen 9. Calcium + aluminum chloride calcium chloride + aluminum 10. Mercury (I) nitrate + sodium carbonate sodium nitrate + mercury (I) carbonate 11. Potassium bromide + aluminum nitrate potassium nitrate + aluminum bromide 12. Calcium phosphate + aluminum sulfate calcium sulfate + aluminum phosphate 13. Rubidium + acetic acid rubidium acetate + hydrogen 8. Zinc + hydrochloric acid zinc chloride and hydrogen gas 9. Potassium hydroxide heated yields potassium oxide and water 10. Magnesium and water produce magnesium hydroxide and hydrogen gas Reaction Prediction 1. Tin (II) and copper (II) sulfate 2. Iron (III) nitrate and sodium chromate 3. Calcium and iodine 4. Magnesium and sulfuric acid 5. Calcium oxide electrolyzed 6. Carbon and oxygen 7. Sodium carbonate and hydrochloric acid 8. Iron (II) sulfide electrolyzed 9. Platinum (II) and lead (II) nitrate 10. Lithium oxide and water 11. C2H4 + O2
Unit 8 Packet - Page 11 of 18 WRITING CHEMICAL EQUATIONS Write balanced equations for the following reactions after identifying the type of reaction. 1. aluminum sulfate + calcium phosphate REACTION TYPES 1. Synthesis: (or composition): 2 or more substances combine to form 1 new substance Unit 8 Packet - Page 12 of 18 2. magnesium chloride + manganese (III) nitrate 3. Hydrogen gas + oxygen gas Ex s: A + X AX 4. Strontium metal + copper (II) nitrate 5. copper (II) oxide + sulfuric acid 2. Decomposition: A single substance produces 2 or more simpler substances AX A + X 6. nitrogen gas + lithium metal Ex s: 7. C4 H8 + O2 8. sodium bromide + oxygen gas Electrolysis: Ex: 9. copper (II) nitride (heated) 10. potassium metal + water 3. Single Displacement (Replacement): 1 element replaces a similar element in a cmpd A + BX AX + B 11. C3 H8 + oxygen gas Ex s: 12. ammonium sulfate + sodium chloride 13. NiO + S
4. Double Displacement (Replacement): The ions of 2 cmpds switch places to form 2 new cmpds. Unit 8 Packet - Page 13 of 18 Double Displacement Reactions & Solubility Rules: Unit 8 Packet - Page 14 of 18 AX + BY AY + BX *often one of the new cmpds will be a ppt. Ex s: 5. Combustion: When a substance combines with oxygen releasing a large amount of energy in the form of light and heat. Often combustions involve a hydrocarbon : cmpd containing C and H Ex. CxHy + O2 CO2 + H2O Group Practice: ID, Write & Balance the following equations: 1. C2H4 + O2 Solubility Rules: Answer the following questions in the space provided. 1. Use your solubility rules to determine if the following substances are soluble (S) or insoluble (I) in water. a. NaC2H3O2 f. K3PO4 b. Li2SO4 g. CaCO3 c. Barium hydroxide h. NaCl d. AgCl i. PbI2 e. MgBr2 j. HNO3 Practice Writing Dissolution of Solids Equations: Write the net ionic equation for the dissolution of the following compounds. Sample: BaCl2 (s) Ba +1 (aq) + 2Cl -1 (aq) 2. Barium + Copper (II) chloride a. Na3PO4 (s) 3. O2 + Ca b. K2SO4 (s) c. KOH (s) 4. PbCl4 + Al(NO3)3 d. CaI2 (s) 5. CaCl2 e. Mg(NO3)2 (s)
Net Ionic Equations: Unit 8 Packet - Page 15 of 18 Steps for writing a net ionic equation 1. Write a balanced equation. 2. Use your solubility rules to determine solubility and break soluble compounds into ions (with charges!). Leave insoluble compounds together without any charges! 3. Cancel out spectator ions if everything cancels write no net reaction. 4. Write the final equation include state symbols! Example 1: Solubility Rules and Net Ionic Equations Worksheet Which of the following compounds are soluble in water? RbOH CrCO3 PbCl2 TiI BaS Which of the following compounds are insoluble in water? NH3 (g) Ba(OH)2 PbI2 CaSO4 K2SO3 Write net ionic equations for the following reactions: 1. Ba(NO3)2 + Na2SO4 BaSO4 + 2 NaNO3 Unit 8 Packet - Page 16 of 18 KC2H3O2 (NH4)3PO4 AgNO3 + MgCl2 2. sodium hydroxide + zinc (II) nitrate sodium nitrate + zinc (II) hydroxide Example 2: HNO3 + Ba(OH)2 3. PbCl2 + Na2SO4 You try: K2S + Al(NO3)3 4. Silver nitrate and calcium bromide
Unit 8 Packet - Page 17 of 18 5. sulfuric acid and sodium chloride produce hydrochloric acid and sodium sulfate Pg 265-267 Activity Series Unit 8 Packet - Page 18 of 18 1. What is the activity series 2. Where are the most active elements found in the series? 3. Look at the sample Questions 8-6 on pg 266 then do the practice questions 4. Do the section review 1-2 on page 267. 6. LiOH + H2S Activity Series Practice (Use the series for single displacement reactions or synthesis reactions with oxygen): I. Based on the activity series of metals and halogens, circle the element within each pair that is more likely to replace the other in a compound? K and Na Al and Ni Bi and Cr Cl and F Cl and I Fe and Sr I and F Au and Ag 7. aluminum chloride and iron (III) nitrate II. Using the activity series of metals and halogens, predict whether each of the possible reactions listed below will occur. For the reactions that will occur, write the products and balance the equation: Ni(s) + CuCl2(aq) Zn(s) + Pb(NO3)2(aq) Cl2(g) + KI(aq) Cu(s) + FeSO4(aq) 8. ammonium chloride + potassium hydroxide potassium chloride + ammonia (g) + water Ba(s) + H2O(l) Na2SO4(aq) + Ba(NO3)2(aq) CuCl2(aq) + Mg(NO3)2(aq) III. Use the activity series to predict whether each of the following synthesis reactions will occur, and write the chemical equations for those predicted to occur: 9. rubidium carbonate + strontium acetate Ca(s) + O2(g) Ni(s) + O2(g) Au(s) + O2(g)