NWTC General Chemistry Ch 08

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NWTC Chemistry Ch 8

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  • When barium chloride is poured into a solution of sodium sulfate, a white precipitate of barium sulfate forms.
  • NWTC General Chemistry Ch 08

    1. 1. Chapter 8 Chemical EquationsFlames andsparks resultwhen aluminumfoil is droppedInto liquidbromine. Introduction to General, Organic, and Biochemistry 10e John Wiley & Sons, Inc Morris Hein, Scott Pattison, and Susan Arena
    2. 2. Chapter Outline8.1 The Chemical Equation8.2 Writing and Balancing Chemical Equations8.3 Information in a Chemical Equation8.4 Types of Chemical Equations8.5 Heat in Chemical Reactions8.6 Global Warming: The Greenhouse Effect Copyright 2012 John Wiley & Sons, Inc
    3. 3. The Chemical Equation Chemical shorthand for a chemical reaction. 4Al(s) + 3O2(g) 2Al2O3(s) 1. Reactants  Products 2. Whole number coefficients indicate numbers of each substance participating in the reaction. 3. Special conditions for the reaction are often written over the arrow. (Δ means heat is supplied to the reaction.) 4. Physical states of each substance are indicated.Review Question 1: Purpose of balancing2012 John Wiley & Sons, Inc Copyright chemical reaction?
    4. 4. The Chemical EquationReview Question 6 Mg(s) + 2HCl(aq) H2(g) + MgCl2(aq) NaOH(aq) + HCl(aq) H2O(l) + NaCl(aq) Copyright 2012 John Wiley & Sons, Inc
    5. 5. Your Turn!In the reaction: CuSO4 + BaBr2 CuBr2 + BaSO4a. BaBr2 and BaSO4 are reactantsb. BaSO4 and CuBr2 are productsc. CuSO4 and BaSO4 are reactantsd. CuSO4 and BaBr2 are products Copyright 2012 John Wiley & Sons, Inc
    6. 6. Writing and Balancing R = reactants Chemical Equations P = products A balloon filled with a hydrogen and oxygen gas explodes when heated. The product is water vapor. 1. Identify the reaction Hydrogen gas + oxygen gas  water gas 2. Write the unbalanced equation H2(g) + O2(g)  H2O(g) 3. Balance the equation R 2H 2O R 4H 2O 2 H2(g) + O2(g)  2 H2O(g) P 2H 1O 4 P 4H 2O2O A balanced equation has the same number of each kind of atom on each side of the equation.Review Question 2: What do the numbers in John Wiley & Sons, Inc Copyright 2012 front represent?
    7. 7. Writing and Balancing Chemical EquationsPhosphorus burns in air to produce diphosphorus pentoxide.1. Identify the reaction phosphorus + oxygen  diphosphorus pentoxide2. Write the unbalanced equation P4 + O2  P2O53. Balance the equation R 4P 10 O 2O P4 + 5 O2  2 P2O5 P 2P 4 10 O 5OHint: Start with most complex compound. Review Question 5: How do Copyright 2012 John Wiley & Sons, Inc you account for the atoms?
    8. 8. Your Turn!Given the unbalanced equation: HCl + NH3  NH4Cl When properly balanced, the sum of the balancing coefficients isa. 7b. 5 HCl + NH3  NH4Clc. 3d. 4e. 6 Copyright 2012 John Wiley & Sons, Inc
    9. 9. Your Turn!Given the unbalanced equation: NH3  H2 + N2 When properly balanced, the sum of the balancing coefficients isa. 3b. 6 2NH3  3H2 + N2c. 9d. 12 Copyright 2012 John Wiley & Sons, Inc
    10. 10. Writing and Balancing Chemical EquationsZinc metal reacts with silver nitrate to produce zinc nitrate and silver metal.1. Identify the reaction zinc + silver nitrate  zinc nitrate + silver2. Write the unbalanced equation Zn + AgNO3  Zn(NO3)2 + Ag3. Balance the equation R 1 Zn 1 Ag 1 NO3 2 2 Zn + 2AgNO3  Zn(NO3)2 + 2 Ag P 1 Zn 1 Ag 2 NO3 2 Hint: Balance polyatomic ions as a unit. Copyright 2012 John Wiley & Sons, Inc
    11. 11. *Your Turn!Given the unbalanced equation: Co + CuSO4 Co2(SO4)3 + Cu When properly balanced, the sum of the balancing coefficients isa. 6b. 7 2Co + 3CuSO4 Co2(SO4)3 + 3Cuc. 8d. 9e. 10 Copyright 2012 John Wiley & Sons, Inc
    12. 12. Your Turn!Given the unbalanced equation: Al(OH)3 + H2SO4 Al2(SO4)3 + H2O When properly balanced, the sum of the balancing coefficients isa. 4b. 9 2Al(OH)3 + 3H2SO4 Al2(SO4)3 + 6H2Oc. 12d. 24 Copyright 2012 John Wiley & Sons, Inc
    13. 13. Writing and Balancing Chemical EquationsEthylene burns in air to produce carbon dioxide and water.1. Identify the reaction ethylene + oxygen  carbon dioxide + water2. Write the unbalanced equation C2H4 + O2  CO2 + H2O3. Balance the equation R 2C 4H 6 2O C2H4 + 3 O2 2 CO2 + 2 H2O P 1C 2 4 2H 4+2 4+1 2+1 O Hint: Balance hydrogen and oxygen last. Copyright 2012 John Wiley & Sons, Inc
    14. 14. Acetylene (C2H2) burns in air to produce carbon dioxide and water.1. Identify the reaction acetylene + oxygen  carbon dioxide + water2. Write the unbalanced equation C2H2 + O2  CO2 + H2O3. Balance the equation R 2C 4 4 2H 10 5 O 2O 5 P 1C 4C 2 4 2H 8+2 4+1 2+1 O2(C2H2 + O2 2 CO2 + H2O ) 2 Hint: Use a fraction to balance O, then multiply all coefficients by two to eliminate the fraction.2 C2H2 + 5 O2  4 CO2 + 2 H2O Copyright 2012 John Wiley & Sons, Inc
    15. 15. Your Turn!Given the unbalanced equation: C2H6 + O2 CO2 + H2O When properly balanced, the sum of the balancing coefficients isa. 23b. 19 2C2H6 + 7O2 4CO2 + 6H2Oc. 17d. 9e. 13 Copyright 2012 John Wiley & Sons, Inc
    16. 16. Your Turn!Given the unbalanced equation: C3H8 + O2 CO2 + H2O When properly balanced, the sum of the balancing coefficients isa. 7b. 9 C3H8 + 5O2 3CO2 + 4H2Oc. 15d. 23e. 13 Copyright 2012 John Wiley & Sons, Inc
    17. 17. Information in a Chemical Equation Copyright 2012 John Wiley & Sons, Inc
    18. 18. Information in a Chemical Equation H2(g) + F2(g)  2HF(g) 1 molecule 1 molecule 2 molecules 2 atoms H 2 atoms F 2 atoms H + 2 atoms F 1 mol H2 1 mol F2 2 mol HF How many moles of HF can be made from 2 moles of hydrogen gas and 2 moles of fluorine gas? 4 moles of hydrogen fluoride gas What is conserved? Atoms! Copyright 2012 John Wiley & Sons, IncReview Question 3
    19. 19. Your Turn!How many molecules of oxygen gas are needed to burn 2 molecules of propane according to the balanced equation ? C3H8 + 5O2 3CO2 + 4H2Oa. 5 molecules of oxygenb. 6 molecules of oxygenc. 10 molecules of oxygend. 15 molecules of oxygen Copyright 2012 John Wiley & Sons, Inc
    20. 20. Types of Chemical Equations1. Combination Reactions A+B AB2. Decomposition Reactions AB A+B3. Single-Displacement A + BC B + AC or A + BC C + BA4. Double-Displacement A B+ CD AD + CB Copyright 2012 John Wiley & Sons, Inc
    21. 21. Combination Reactions1. metal + oxygen  metal oxide A+B AB 2Mg(s) + O2(g)  2MgO(s) 4Fe(s) + 3O2(g)  2Fe2O3(s)2. nonmetal + oxygen  nonmetal oxide C(s) + O2(g)  CO2(g) 2N2(s) + O2(g)  2N2O (g) Copyright 2012 John Wiley & Sons, Inc
    22. 22. Combination Reactions3. metal + nonmetal  salt A+B AB 2Al(s) + 3Br2(l)  2AlBr3(s) 2K(s) + I2(s)  2KI(s)4. metal oxide + water  metal hydroxide K2O(s) + H2O(l)  2KOH(aq) SrO(s) + H2O(l)  Sr(OH)2(aq) Copyright 2012 John Wiley & Sons, Inc
    23. 23. Combination Reactions5. nonmetal oxide + water  oxy-acid A+B AB SO3(g) + H2O(l)  H2SO4(aq) P2O5(s) + 3H2O(l)  2H3PO4(aq) N2O5(s) + H2O(l)  2HNO3(aq) Copyright 2012 John Wiley & Sons, Inc
    24. 24. Decomposition Reactions1. Metal oxides decompose into metals and oxygen gas. 2HgO(s) 2Hg(l) + O2(g) AB A+B 2PbO2(s) 2PbO(s) + O2(g)2. Metal carbonates form metal oxides and CO2. Na2CO3(s) Na2O + CO2(g)3. Metal bicarbonates form metal carbonates, CO2 and H2O. NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(g) Copyright 2012 John Wiley & Sons, Inc
    25. 25. Decomposition Reactions4. Other examples: AB A+B 2Hg2O2(aq) 2H2O(l) + O2(g) 2NaClO3(s) 2NaCl(s) + 3O2(g) Copyright 2012 John Wiley & Sons, Inc
    26. 26. Single Displacement ReactionsIf A is a metal: A + BC B + ACIf A is a nonmetal: A + BC C + BAZn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)When pieces of zinc metal are placedin hydrochloric acid, hydrogenbubbles form immediately. Copyright 2012 John Wiley & Sons, Inc
    27. 27. Activity SeriesReview Question 7 a More active elements can replace less active elements.2Al(s) + 3CuCl2(aq) 2AlCl3(aq) +73Cu (s) Review Question bHg(l) + CuSO4(aq) no reaction Copyright 2012 John Wiley & Sons, Inc
    28. 28. Your Turn!Consider the following reactions: A(s) + HCl(aq)  no reaction B(s) + 2HCl(aq)  BCl2(aq) + H2(g)What is the correct activity series?a. least active A < B < H most activeb. least active A < H < B most activec. least active B < H < A most active Copyright 2012 John Wiley & Sons, Inc
    29. 29. Single Displacement Reactions1. Metal + acid  H2 + salt Fe(s) + 2HCl(aq) FeCl2(aq) + H2 (g) Cu(s) + HCl(aq)  no reaction2. metal + water  H2 + metal oxide or metal hydroxide 2K(s) + 2H2O(l) 2KOH(aq) + H2 (g) 3Fe(s) + 4H2O(g) Fe3O4(s) + 4H2 (g) Copyright 2012 John Wiley & Sons, Inc
    30. 30. Single Displacement Reactions3. Metal + salt  metal + salt Sn(s) + 2AgNO3(aq) Sn(NO3)2(aq) + Ag(s) Zn(s) + AlCl3(aq)  no reaction4. halogen + halide salt halogen + halide salt F2(g) + 2NaCl(aq) 2NaF(aq) + Cl2 (g) I2(s) + 2NaCl(aq) no reaction Copyright 2012 John Wiley & Sons, Inc
    31. 31. Your Turn!The reaction: Ba(s) + PtCl2(aq) BaCl2(aq) + Pt(s), will occur ifa. Pt is more active than Bab. Ba is more active than Ptc. Ba is more active than Od. O is more active than Pt Copyright 2012 John Wiley & Sons, Inc
    32. 32. Your Turn!The likely products of the reaction between Al and NiCl2 area. AlNi and Cl2b. AlCl2 and Nic. AlCl and Nid. AlCl3 and Nie. no reaction Copyright 2012 John Wiley & Sons, Inc
    33. 33. Double Replacement ReactionsA B+ CD AD + CBCations exchange anionsPb(NO3)2(aq) + 2KI(aq)  PbI2(s) + 2KNO3(aq)Evidence of chemical change:1. Evolution of heat2. Formation of precipitate3. Formation of gas bubbles Copyright 2012 John Wiley & Sons, Inc
    34. 34. Neutralization ReactionsDouble replacement: A B+ CD AD + CBacid + base  salt + water + heatHCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)Detected by increase in temperature (release of heat).H2SO4(aq) + Ba(OH)2(aq)  BaSO4(s) + 2H2O(l)Detected by increase in temperature and formation of a cloudy precipitate. Copyright 2012 John Wiley & Sons, Inc
    35. 35. Metal Oxide + Acid ReactionsDouble replacement: A B+ CD AD + CBmetal oxide + acid  salt + waterHeat is released by the production of waterZnO(s) + 2HCl(aq)  ZnCl2(aq) + H2O(l)Na2O(s) + 2HCl(aq)  2NaCl(aq) + H2O(l) Copyright 2012 John Wiley & Sons, Inc
    36. 36. Precipitation ReactionsDouble replacement: A B+ CD AD + CBAn insoluble product (precipitate) is formed and indicated by placing an (s) after its formula in the equation.Check the solubility table in Appendix V tosee if a precipitate forms.BaCl2(aq) + Na2SO4(aq) BaSO4(s) + 2NaCl(aq)2NaCl(aq) + Hg2(NO3)2(aq) 2NaNO3(aq) + Hg2Cl2(s) Copyright 2012 John Wiley & Sons, Inc
    37. 37. Gas Forming ReactionsDouble replacement: A B+ CD AD + CBNaCl(s) + H2SO4(l) NaHSO4(s) + HCl(g)Na2S(aq) + 2HCl(aq) H2S(g) + 2NaCl (s)H2SO4(aq) + 2NaCN(aq) Na2SO4(aq) + 2HCN(g)Double replacement reactions that form H2CO3, H2SO3 or NH4OH are quickly followed by the decomposition of these compounds into gases (indirect gas production). Copyright 2012 John Wiley & Sons, Inc
    38. 38. Indirect Gas Forming Reactionsmetal carbonate + acid  salt + CO2(g) + H2O(l)Na2CO3(aq) + 2HCl(aq)  2NaCl(aq) + CO2(g) + H2O(l)metal sulfite + acid  salt + SO2(g) + H2O(l)Na2SO3(aq) + 2HCl(aq)  2NaCl(aq) + SO2(g) + H2O(l)ammonium salt + base  salt + NH3(g) + H2O(l)NH4NO3(aq) + NaOH(aq)  NaNO3(aq) + NH3(g) + H2O(l) Copyright 2012 John Wiley & Sons, Inc
    39. 39. Your Turn!What are the likely products of the reaction of copper(II) oxide with nitric acid?a. CuNO3 + H2Ob. Cu(NO3)2 + H2Oc. Cu(NO2)2 + H2Od. CuNO2 + H2O CuO(s) + 2HNO3(aq) Cu(NO3)2(aq) + H2O(l) Copyright 2012 John Wiley & Sons, Inc
    40. 40. Your Turn!What are the likely products of the reaction of sodium sulfide with iron(III) chloride?a. FeS + NaClb. FeS3 + NaClc. Fe3S + NaCld. Fe2S3 + NaCl 2FeCl3(aq) + 3Na2S(aq) Fe2S3(s) + 6NaCl(aq) Copyright 2012 John Wiley & Sons, Inc
    41. 41. Your Turn!What are the likely products of the reaction of sodium hydrogen carbonate with hydrochloric acid?a. NaCl + H2CO3b. NaCl + H2O + CO2c. NaCl + H2O + CO3d. NaCl + H2 + CO3 NaHCO3(aq) + HCl(aq)  NaCl(aq) + H2O(l) + CO2(g) Copyright 2012 John Wiley & Sons, Inc
    42. 42. Heat in Chemical Reactions Endothermic vs Exothermic Endothermic reactions absorb heat O2(g) + N2(g) + 181 kJ  2NO(g) Exothermic reactions release heat 2 Al(s) + Fe2O3(s) 2Fe(s) + Al2O3(s) + 852 kJ The amount of heat absorbed or released is the heat of reaction. Copyright 2012 John Wiley & Sons, IncReview Question 4
    43. 43. Endothermic Reactions Copyright 2012 John Wiley & Sons, Inc
    44. 44. Exothermic Reactions Copyright 2012 John Wiley & Sons, Inc
    45. 45. Your Turn!Consider the reaction: H2 + I2 + 12.6 kJ 2 HI. When one mole of HI is produced A. 12.6 kJ of energy is absorbed B. 6.3 kJ of energy is absorbed C. 12.6 kJ of energy is released D. 6.3 kJ of energy is released Copyright 2012 John Wiley & Sons, Inc
    46. 46. Global Warming:The Greenhouse Effect Copyright 2012 John Wiley & Sons, Inc
    47. 47. Global Warming: The Greenhouse EffectIncreased carbon dioxide levels have caused a 0.74°C rise in global temperatures over the last 100 years. Copyright 2012 John Wiley & Sons, Inc
    48. 48. QuestionsReview Questions – Did in classPaired Questions (pg 164) – Do 1, 3, 7, 9, 11, 15, 21, 27, 29, 31, 35 , 39, 43 – Practice later 2, 6, 12, 16, 20, 24, 28, 32, 36, 40, 44 Copyright 2012 John Wiley & Sons, Inc 1-48

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