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Types of Chemical Reactions

Types of Chemical Reactions. Honors Chemistry Mr. Rivas. Types of Chemical Reactions. Combustion Rxn Synthesis (Combination) Rxn Decomposition Rxn Single Replacement Rxn Double Replacement Rxn Acid-Base Reactions Redox Rxn. Combustion Rxn.

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Types of Chemical Reactions

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  1. Types of Chemical Reactions Honors Chemistry Mr. Rivas

  2. Types of Chemical Reactions • Combustion Rxn • Synthesis (Combination) Rxn • Decomposition Rxn • Single Replacement Rxn • Double Replacement Rxn • Acid-Base Reactions • Redox Rxn

  3. Combustion Rxn • A substance reacts with O2 to form compounds that contain oxygen atom(s) • General Form: AB + O2 AO + BO or A + O2  AO

  4. Combustion Rxn - Example • The burning of charcoal is an example of a combustion reaction • C(s) + O2(g)  CO2(g) • Another important group of combustion reactions is the burning of hydrocarbons (gasoline is a mixture of hydrocarbons) • Hydrocarbons contain only carbon and hydrogen atoms.

  5. Three things are required to sustain a fire:

  6. Combustion Rx - Hydrocarbons • One important group of hydrocarbons are the alkanes (hydrocarbons with only single bonds) • They have the general formula: CnH2n+2 Where n is the number of carbon atoms

  7. Combustion Rx - Hydrocarbons • The formula of a hydrocarbon with 4 carbons (n = 4) would then be: C4H2x4+2C4H10 • What would be the formula of a hydrocarbon with 8 carbons? C8H18

  8. Combustion Rx - Hydrocarbons • To name the hydrocarbons we use the following prefixes: • 1 Meta 6 Hexa • 2 Eta 7 Hepta • 3 Propa 8 Octa • 4 Buta 9 Nona • 5 Penta 10 Deca

  9. Combustion Rx - Hydrocarbons • CH4 Methane Natural Gas • C2H6 Ethane • C3H8 Propane BBQ balloon gas • C4H10 Butane Cigarette lighter • C5H12 Pentane • Etc.

  10. Combustion Rx - Hydrocarbons • When hydrocarbons burn they produce: Carbon dioxide and water. • The equation for the combustion of methane is: CH4 + 2O2 CO2 + 2H2O

  11. Is this equation already balanced?

  12. Can you balance this combustion reaction chemical equation?

  13. Combustion Rx – Single elements • Elements can also combust. Some rapidly: 2Mg + O2 2MgO • Some slowly (Rusting) 4Fe + 3O2 2Fe2O3 (Catalyst) • These reactions can also be classified as synthesis reactions.

  14. Combustion Rxn - Exercises • Write a balance equation for the following combustion reaction: • Li + O2 Li2O • Ca + O2 CaO • CO + O2  CO2 • Combustion of propane

  15. Combustion Rxn - Exercises • Answers: • 4Li + O2 2Li2O • 2Ca + O2 2CaO • 2CO + O2  2CO2 • C3H8 + 5O2  3CO2 + 4H2O

  16. Combustion Rxn - Exercises • Answer questions Worksheet 9-2: Combustion Reactions The fire acts as the activation energy to initiate the combustion reaction

  17. Synthesis Rxn • In this reactions, two or more substances are combined together to form a single more complex compound. • General form: A + B = AB

  18. Synthesis Rxn - Example • The reaction between chlorine gas and sodium: 2Na(s) + Cl2(g)  2NaCl(s) • Many combustion reactions can also be classified as synthesis reactions: 2H2(g) + O2(g)  2H2O(g) (This is an explosive reaction)

  19. Synthesis Rxn - Example • The formation of acid rain results from synthesis reactions in the atmosphere: 2S(s) + 3O2 2SO3(g) SO3 + H2O  H2SO4 (sulfuric acid) • This synthesis reaction started the “Green Revolution” N2(g) + 3H2(g)  2NH3(g) (ammonia)

  20. Synthesis Rxn - Exercises • Write a balance equation for the following synthesis reactions: • K + I2 KI • Sr + O2 SrO • Na + S  Na2S • H2 + O2  H2O

  21. Synthesis Rxn - Exercises • ANSWERS: • 2K + I2 2KI • 2Sr + O2 2SrO • 2Na + S  Na2S • 2H2 + O2  2H2O

  22. Decomposition Rxn • A single compound produces two or more substances. • General Form: AB  A + B

  23. Decomposition Rxn - Examples • When heated, carbonates decompose to form an oxide and carbon dioxide CaCO3(s)  CaO(s) + CO2(g) limestone quicklime CuCO3(s)  CuO(s) + CO2(g)

  24. Decomposition Rxn - Examples • Hydrogen peroxide slowly decomposes into water and oxygen (light speeds up the decomposition) 2H2O2(l)  2H2O(l) + O2(g) • When heated, sucrose (sugar) decomposes into carbon and water C12H22O11(s)  12C(s) + 11H2O(g)

  25. Synthesis & Decomposition Rxn - Exercises • Answer questions Worksheet 9-2: Part B: Synthesis & Decomposition Reactions

  26. Single Replacement Rxn • A free element replaces a less active element in a compound. • General Form: A + BC  AC + B (If A is more active than B)

  27. Single Replacement Rxn -Examples • Hydrogen in hydrochloric acid is replaced by Zn, a more active element. Zn(S) + HCl(aq)  ZnCl2(aq) + H2(g) • Bromine in sodium bromide is replaced by Cl, a more active element. Cl2(g) + NaBr(aq)  NaCl(aq) + Br l • Copper in copper sulfate is replaced by Mg, a more active element. Mg(s) + CuSO4(aq)  MgSO4(aq) + Cu(S)

  28. Li Most Active K Ba Sr Ca Na Mg Al Mn Zn Fe Cd Co Ni Sn Pb H Cu Ag Hg Au Least Active The Activity Series of Metals

  29. Activity Series of the Halogens • Fluorine Most active • Chlorine • Bromine • Iodine Least active

  30. Single Replacement Rxn - Exercises Complete the following reaction. Enter NR if no reaction is predicted. • Cu + AgNO3 • Fe + CuSO4 • Mg + CaSO4 • Br2 + KI 

  31. Single Replacement Rxn - Answers • Cu + 2AgNO3 Cu(NO3)2 + 2Ag • Fe + CuSO4 FeSO4 + Cu • Mg + CaSO4 NR • Br2 + 2KI  2KBr + I2

  32. Single Replacement Rxn - Exercises • Answer questions Worksheet 9-2: Part C: Single Replacement Reactions

  33. Double Replacement Rxn • The positive ion of one compound combines with the negative ion of the other compound and vice versa. • General Form: AB + CD  CB + AD • The solubility rules determine if a double replacement reaction will take place.

  34. Double Replacement Rxn - Example • The silver ion of silver nitrate forms an insoluble compound when it combines with the chloride ion of sodium chloride AgNO3(aq) + NaCl(aq) NaNO3(aq) + AgCl(s) • The lead(II) ion of lead(II) nitrate forms and insoluble precipitate with the iodide ion of potassium iodide. Pb(NO3)2 + 2KI  PbI(s) + 2KNO3

  35. Solubility Rules • NO3– All nitrates are soluble • Cl–All chlorides are soluble except: • AgCl, Hg2Cl2, PbCl2, and CuCl • SO42– All sulfates are soluble except: • BaSO4, PbSO4, SrSO4, CaSO4, and Ag2SO4 • CO32– All carbonates are insoluble except: • NH4+ and those alkaline metals • OH– All hydroxides are insoluble except: • Alkaline metals, Ba(OH)2, Sr(OH)2, Ca(OH)2 • S2– All sulfides are insoluble except: • Alkali, alkaline earth metals, and NH4+

  36. Double Replacement Rxn - Exercises • Complete the following reaction indicate NR if no reaction takes place: • Pb(NO3)2 + K2SO4 • SrBr2 + CuSO4 • MgCl2 + NH4NO3 • CaF2 + Li2CO3 • BeI2 + Li3PO4

  37. Double Replacement Rxn - Answers • Complete the following reaction indicate NR if no reaction takes place: • Pb(NO3)2 + K2SO4 PbSO4 + 2KNO3 • SrBr2 + CuSO4 SrSO4 + CuBr2 • MgCl2 + NH4NO3 NR • CaF2 + Li2CO3 CaCO3 + 2LiF • 3BeI2 + 2K3PO4 Be3(PO4)2 + 6KI

  38. Double Replacement Rxn - Exercises • Answer questions Worksheet 9-2: Part C: Single Replacement Reactions and Part D: Double Replacement Reactions

  39. Acid-Base Rxn • According to the Brønsted-Lowry theory: • A base is any compound which can accept a proton. • An acid is any compound which can donate a proton. • In an acid-base reaction, an acid and a base will react to form a salt and water.

  40. Acid-Base Rxn – Example • Hydrochloric acid (a proton donor) reacts with sodium hydroxide (a proton acceptor) to form sodium chloride (a salt) and water HCl + NaOH  NaCl + H2O acid base salt water

  41. Redox Reaction • A REDuction-OXidation reaction is one in which an element is oxidized and another one reduced. • Oxidation is the loss of electrons while • Reduction is the gain of electrons. • Many of the reactions that we have covered are redox reactions.

  42. Remember… OIL RIG

  43. Redox Reaction - Example • The reaction of Magnesium and chlorine is an example of redox reaction: loses 2 electrons Mg + Cl2 MgCl2 gains 2 electrons

  44. Predicting Chemical Reactions • Several factors such as temperature, pressure, physical state, acidity, etc, influence a chemical reaction. • The only way to determine the results of a chemical reaction is by experimentation in the lab. • Nevertheless, based on our classification of the types of reactions, we can make an educated guess.

  45. Predicting chemical reactions Predict the results of the following reactions: • K + I2 • C12H26 + O2 • Li + Pb(NO3)2 • MgCO3  • CuSO4 + NaOH  • LiOH + HCl 

  46. Predicting chemical reactions Predict the results of the following reactions: • 2K + I2 2KI • 2C12H26 + 37O2 24CO2 + 26H2O • 2Li + Pb(NO3)2 2LiNO3 + Pb • MgCO3  MgO + CO2 • CuSO4 + 2NaOH  Na2SO4 + Cu(OH)2 • LiOH + HCl  LiCl + H2O

  47. Predicting chemical reactions • Answer questions Worksheet 9-2: Part E: Potpourri of reactions

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