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Chemical Reactions

Chemical Reactions. Chapter 8. Chemical Reactions. Chemical Reaction Rearranges atoms to create new substances Evidence of a Chemical Reaction Temperature change Color change Production of light Production of gas Creation of a precipitate (solid). end. Chemical Equations.

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Chemical Reactions

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  1. Chemical Reactions Chapter 8

  2. Chemical Reactions • Chemical Reaction • Rearranges atoms to create new substances • Evidence of a Chemical Reaction • Temperature change • Color change • Production of light • Production of gas • Creation of a precipitate (solid) end

  3. Chemical Equations • Chemical Equations (Molecular Equation) • Reactants • On the LEFT • Products • On the Right • State of Matter: • (s), (l), (g), (aq) • aq- aqueous (dissolved in water) 2H2(g) + O2(g) 2H2O(l) Yields/Forms/Creates/Produces end

  4. Chemical Equations • The Law of Conservation of Matter • Matter CANNOT be created or destroyed! • Every atom at the start, must be at the end! • MUST BALANCE EQUATIONS!!! end

  5. Chemical Equations • Steps to balancing chemical equations: • Write Equation • List Elements • Multiply by Coefficients • MINOH • Elements in Multiple Places LAST • NEVER Change the Subscripts! end

  6. Chemical Equations • ___ NaCl + ___ F2  ___ NaF + ___ Cl2 • ___ KClO3  ___ KCl + ___ O2 end

  7. Chemical Equations • ___ Pb(NO3)2 + ___ KI  ___ PbI2 + ___ KNO3 • ___ CH4 + ___ O2  ___ CO2 + ___ H2O end

  8. Chemical Equations • Complete #1-5 on “Balancing Chemical Equations”

  9. Chemical Equations • Word Equations • Box Reactants and Underline Products • Write formulas • Ionic vs. Covalent!!! • Balance Equation end

  10. Chemical Equations • Write and balance the following equations: • Potassium metal is placed in water yielding hydrogen gas and potassium hydroxide • Potassium hydroxide is formed from potassium oxide being placed into water • Nitrogen gas plus oxygen gas react and form dinitrogen pentoxide end

  11. Chemical Equations • Complete #1-4 on “Word Equations”

  12. Chemical Reactions • 5 Basic Types: end

  13. Chemical Reactions • Synthesis • 2 reactants combine to form 1 product A + B  AB ___Mg + ___O2 ___MgO end

  14. Chemical Reactions • Decomposition • 1 reactant breaks down into 2 products AB  A + B ___H2O2 ___O2 + ___H2O end

  15. Chemical Reactions • Single Replacement • 1 single element replaces an element in a compound A + BC AC + B ___Mg + ___HC2H3O2 ___Mg(C2H3O2)2 + ___H2 Or D + BC BD + C ___Br2 + ___MgI2 ___MgBr2 + ___I2 end

  16. Chemical Reactions • Double Replacement • Reactants switch partners AB + CDAD + CB • Produces a Solid, H2O, or a Gas ___Pb(NO3)2 (aq) + ___KI(aq) ___PbI2 (s) + ___KNO3 (aq) ___NaOH (aq) + ___HCl (aq) ___NaCl (aq) + ___HOH (l) H2O(l) end

  17. Chemical Reactions • Combustion • Combine with O2 (g) • Produces heat and light • Forms CO2(g) and H2O(l) CxHyOz + O2 (g) CO2 (g) + H2O(l) ___C3H8 + ___O2 (g) ___CO2 (g) + ___ H2O(l) ___C2H6O + ___O2 (g) ___CO2 (g) + ___ H2O(l) end

  18. Chemical Reaction • Classify the following: • 2 H2 + O2 2 H2O • Zn + H2SO4 ZnSO4 + H2 • 2 HgO  2 Hg + O2 • AgNO3 + NaCl  AgCl + NaNO3 • 2 C2H6 + 7 O2 4 CO2 + 6 H2O end

  19. Chemical Reaction Complete #1-10 on “Classifying Chemical Reactions”

  20. Predicting Products • Tests for Gases Produced: • H2(g) • Burning splint  “pop” sound • O2(g) • Glowing splint  starts burning • CO2(g) • Burning splint  goes out • Bubbled in lime water  cloudy CO2(g) + Ca(OH)2(aq)  CaCO3(s) + H2O(l) end

  21. Predicting Products • Predicting Products • Identify Rxn Type • Look at Reference Table • Watch Ionic vs. Covalent! end

  22. Predicting Products • Synthesis • 2 Elements Combine  Binary Compound • H2 + O2  • Mg + Cl2  • Metallic Oxide + H2O  Metallic Hydroxide (Base) • Al2O3 + H2O  • Nonmetal Oxide + H2O  Oxyacid • CO2 + H2O  end

  23. Predicting Products • Predict the Products: • N2 + H2 • Al + S  • Cr2O3 + H2O  • SO3 + H2O  end

  24. Predicting Products • Decomposition • Always add: • Heat • Electricity • Light • Binary Compound  2 Element Separated • NaF • Metal Carbonate  Metal Oxide + CO2 • K2CO3  end

  25. Predicting Products • Decomposition (cont…) • Metal Hydrogen Carbonate  Metal Oxide + H2O(l) + CO2(g) • NaHCO3  • Metal Hydroxide  Metal Oxide + H2O • Mg(OH)2  • Metal Chlorate  Metal Chloride + O2 • KClO3  • Oxyacid  Nonmetal Oxide + H2O • H2SO3  end

  26. Predicting Products • Predict the Products: • MgCO3 • PCl5 • Fe(HCO3)2 • HgOH  • Ni(ClO3)2 • H2CO3 end

  27. Predicting Products • Combustion • ALWAYS creates H2O(l) + CO2(g) • Predict the Products • C2H6 is completely burned in the air. • C6H14 is burned in excess oxygen. end

  28. Predicting Products • Single-Replacement • The Activity Series!!! • Single Element ABOVE will replace a LOWER Element Ion • K(s) + ZnCl2(aq) • Ni(s) + ZnCl2(aq)  Zn(s) + KCl(aq) No Rxn end

  29. Predicting Products • Single-Replacement (cont…) • Metal + Salt(aq) Other Metal + New Salt(aq) • Mg + FeCl3(aq)  • Active Metal + H2O  Metal Hydroxide + H2 • Rb + H2O  • Metal + Acid  Salt(aq) + H2 • Sn + HCl  • Halogen + Halide Salt(aq)  Other Halogen + New Salt(aq) • Cl2 + NaI(aq)  end

  30. Predicting Products • Predict the products: • Sr + HCl  • AlP + K  • Cu + H2S  • Ca + H2O  • Br2 + CsI  end

  31. Predicting Products • Double-Replacement • The Solubility Rules! • All Products Aqueous = No Reaction! • Salt(aq) + Salt(aq) New Salt(aq) + New Salt(s) • Pb(NO3)2(aq) + KI(aq) • Acid + Base  Salt + H2O(l) (Neutralization Reaction) • H3PO4 + Mg(OH)2  • Acid + Metal Carbonate  New Salt(aq) + H2O(l) +CO2(g) • H2SO4 + Al2(CO3)3 end

  32. Predicting Products • Predict the Products: • NaOH + H2SO4 • AgNO3 + CuCl2 • HCl + CaCO3  end

  33. Predicting Products • Al + N2 • Ca(OH)2 • Mg + Fe2(SO4)3 • Pb(NO3)2 + HI • CH4O is burned in excess oxygen.

  34. Aqueous Reactions • Aqueous Reactions • Dissolved in WATER • Single and Double Replacement Rxns • Solubility Rules!!! • NO SOLID/GAS/WATER = ALL AQUEOUS = NO RXN • LETS SING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :D • NaF Co(NO3)2 • Al(OH)3 BaSO4 • Mg3(PO4)2 (NH4 )2S end

  35. Aqueous Reactions • Predict Products • NaOH(aq) + HNO3(aq) • CuS(aq) + KCl(aq) • ___Pb(NO3)2(aq) + ___KI(aq) end

  36. Aqueous Reactions • Cations and Anions separate when dissolved • Complete Ionic Equation • Shows all ions Pb2+(aq) + 2NO3-(aq) + 2K+(aq) + 2I-(aq) PbI2(s)+2K+(aq)+2NO3-(aq) end

  37. Aqueous Reactions Pb2+(aq)+ 2NO3-(aq)+ 2K+(aq)+ 2I-(aq)PbI2(s)+2K+(aq)+2NO3-(aq) • Ions on both sides are Spectator Ions • Don’t participate in the reaction • Net Ionic Equation • Omit Spectator Ions • Pb2+(aq) + 2I-(aq) PbI2(s) • All Ions Spectators = No Reaction end

  38. Aqueous Reactions • Rules for writing ionic equations • Write balanced Molecular Equation • with States of Matter! • Write Complete Ionic Equation • Remember: solids, liquids, and gases ARE NOT ions!!! • Cancel spectator ions • Write Net Ionic Equation end

  39. Aqueous Reactions • Aqueous calcium chloride reacts with aqueous sodium carbonate • Aluminum metal reacts with aqueous copper (II) chloride • Nitric acid is slowly added to a solution of rubidium hydroxide end

  40. Energy Changes • Chemical Energy • Stored in chemical bonds • Changed during a chemical reaction • Exothermic • Gives off energy • Heat/Light • Endothermic • Takes in energy • Gets cold end

  41. Reaction Rates • Reaction Rate • Speed of reactants becoming products • 5 ways to speed up: • Higher Temperature • More Surface Area (Grind into powder) • Stir • More Reactants • Catalyst end

  42. Extra practice • aqueous Sodium chloride reacts with aqueous ammonium nitrate • aqueous lead (II) nitrate reacts with aqueous sodium sulfide • Potassium metal reacts with aqueous calcium chloride • aqueous sodium carbonate reacts with aqueous magnesium sulfate

  43. Save for rxn rates and energy

  44. Reaction Rates • Reaction Rate • Rate that reactants change to products • Based on Collision Theory end

  45. Reaction Rates • Collision Theory • For a reaction to occur, reactants must collide • In the correct orientation • With enough energy to form an activated complex end

  46. Reaction Rates • Activated Complex (Transition State) • Unstable • Reactants changing to Products • Activation Energy • Energy needed to form an activated complex • A “push start” • Chemical Energy • Stored in bonds • Changes when bonds are broken/formed end

  47. Reaction Rates • Exothermic Reaction • Gives OFF Energy • Produces heat/light • Hand warmers and glow sticks • Energy written as a PRODUCT A + B  C + D + energy Na + Cl2  NaCl + 411kJ Energy end

  48. Reaction Rates Reactants have MORE energy than the Products end

  49. Reaction Rates • Endothermic Reaction • Takes IN Energy • Gets colder • Instant icepacks • Energy written as a REACTANT A + B + energy  C + D 15000 kJ + 6 CO2 + H2O  C6H12O6 + 6 O2 Energy end

  50. Reaction Rates Reactants have LESS energy than the Products end

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