2.  All chemical reactions result in the formation of new substances.  Since we can’t see atoms and molecules, we rely on clues from the reaction to indicate whether a chemical reaction has occurred.  These clues include (but are not limited to)  Change in colour  Change in temperature (absorption or release of heat)  Release of energy as light  Production of gas  Formation of precipitate  Change in odour

3.  In a chemical reaction, atoms are rearranged to make new substances.  There must be the same amount of atoms at the beginning and at the end of the reaction…..the atoms are just differently arranged.  ie. The total mass of the reactants must be the same as the total mass of the products.  For this reason, all chemical equations must be balanced….same amount of each element on the product and the reactant side of an equation.

4. Cl H H H HH H H H2 + Cl2  HCl (unbalanced) H2 + Cl2  2 HCl (balanced) 2 1 2 reactants products 2 H Cl H

5. H 2 + Cl 2 2 HCl ++ Total atoms=Total atoms 2 H, 2 Cl2H, 2 Cl Total Mass=Total Mass 2(1.0) + 2(35.5)2(36.5) 73.0 g=73.0 g

6. There are five types of chemical reactions we will talk about: 1. Synthesis reactions 2. _____________ reactions 3. Single displacement reactions 4. ________________ reactions 5. Combustion reactions You need to be able to identify types of reactions and predict their product(s)

7. 1.Synthesis: A + B  AB 2.Decomposition: AB  A + B 3.Single displacement: A + BC  AC + B 4.Double displacement: AB + CD  AD + CB a)Neutralization: Acid(H) + Base(OH)  salt + H(OH) b)Precipitation c)Production of gas 5.Combustion: AB + oxygen  CO 2 + H 2 O

8. 1. Identify the type of reaction 2. Predict the product(s) using the type of reaction as a model 3. Balance it Don’t forget about the diatomic elements! (HOBrFINCl) For example, Oxygen is O 2 as an element.

9. Synthesis reactions occur when two substances (generally elements ) combine and form a compound. (Sometimes these are called combination or addition reactions.) reactant + reactant  1 product Basically: A + B  AB Example: 2H 2 + O 2  2H 2 O Example: C + O 2  CO 2

10. Synthesis Reaction General form: A + B  AB element orelement or compoundcompound Na + Cl - Na ClNa Cl Na + Cl - 2 Na + Cl 2  2 NaCl

11. (c) McGraw Hill Ryerson 2007 OTHER EXAMPLES… 1. Elements that form ionic compounds: Magnesium metal reacts with oxygen gas to form magnesium oxide. 2Mg + O 2  2MgO (metal oxide)2Mg + O 2  2MgO (metal oxide) 2. Elements that form covalent compounds: Nitrogen gas and oxygen gas join to form dinitrogen monoxide. 2N 2 + O 2  2N 2 O (non-metal oxide)2N 2 + O 2  2N 2 O (non-metal oxide) See pages 258 - 259 SYNTHESIS REACTION (iron + sulphur): http://www.youtube.com/watch?v=A5H6DVe5FAI

12. Here is another example of a synthesis reaction

13. Predict the products. Write and balance the following synthesis reaction equations. Sodium metal reacts with chlorine gas Na (s) + Cl 2(g)  Solid Magnesium reacts with fluorine gas Mg (s) + F 2(g)  Aluminum metal reacts with fluorine gas Al (s) + F 2(g) 

14. Decomposition reactions occur when a compound breaks up into its elements or into a few simpler compounds 1 Reactant  Product + Product In general: AB  A + B Example: 2 H 2 O  2H 2 + O 2 Example: 2 HgO  2Hg + O 2

15. Decomposition Reaction O O O HH HH H H H H O Decomposition reaction 2 H 2 O 2 H 2 O2O2 General form: ABAB + + + compoundtwo or more elements or compounds

16. Another view of a decomposition reaction:

17. (c) McGraw Hill Ryerson 2007 2. Covalent compounds may decompose into elements, like the following:  By running electricity through water, the water molecules decompose into hydrogen and oxygen gases.  2H 2 O  2H 2 + O 2 See page 260 DECOMPOSITION REACTION: http://www.youtube.com/watch?v=Nddwt XEA_Ak

18. Compounds containing carbonates and chlorates are special case decomposition reactions that do not decompose to their elements. Carbonates (CO 3 2- ) decompose to carbon dioxide and a metal oxide Example: CaCO 3  CO 2 + CaO Chlorates (ClO 3 - ) decompose to oxygen gas and a metal chloride Example: 2 Al(ClO 3 ) 3  2 AlCl 3 + 9 O 2 There are other special cases, but we will not explore those in this course

19.  Read section 4.1 & 4.2  Pg 155 # 3-5  Pg 161 # 1, 2, 4, 8, 9

20. Predict the products. Then, write and balance the following decomposition reaction equations: Solid Lead (IV) oxide decomposes PbO 2(s)  Aluminum nitride decomposes AlN (s) 

21. Identify the type of reaction for each of the following synthesis or decomposition reactions, and write the balanced equation: N 2(g) + O 2(g)  BaCO 3(s)  Co (s) + S (s)  NH 3(g) + H 2 CO 3(aq)  NI 3(s)  (make Co be +3) Nitrogen monoxide

22. Single Displacement Reactions occur when one element replaces another in a compound. A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-). element + compound  element + compound A + BC  AC + B (if A is a metal) OR A + BC  BA + C (if A is a nonmetal) (remember the cation always goes first!) When H 2 O splits into ions, it splits into H + and OH - (not H+ and O -2 !!)

23. 1. When A is a metal:  Aluminum foil in a solution of copper(II) chloride produces solid copper and aluminum chloride.  2Al + 3CuCl 2  3Cu + 2AlCl 3 2. When A is a non-metal:  When fluorine is bubbled through a sodium iodide solution, iodine and sodium fluoride are produced.  Fl 2 + 2NaI  I 2 + 2NaF SINGLE REPLACEMENT: http://www.youtube.com/watch?v=hKtynbVtMKc

24. Another view:

25. Write and balance the following single displacement reaction equation: Zinc metal reacts with aqueous hydrochloric acid Zn (s) + HCl (aq)  ZnCl 2 + H 2(g) Note: Zinc replaces the hydrogen ion in the reaction 2

26. Sodium chloride solid reacts with fluorine gas NaCl (s) + F 2(g)  NaF (s) + Cl 2(g) Note that fluorine replaces chlorine in the compound Aluminum metal reacts with aqueous copper (II) nitrate Al (s) + Cu(NO 3 ) 2(aq)  2 2

27. Double Displacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound Compound + compound  compound+ compound AB + CD  AD + CB

28. Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together Example: AgNO 3(aq) + NaCl (aq)  AgCl (s) + NaNO 3(aq) Another example: K 2 SO 4(aq) + Ba(NO 3 ) 2(aq)  KNO 3(aq) + BaSO 4(s) 2

29.  Usually occur between compounds in aqueous solution  Types of DD reactions  Reactions that form solids (precipitates)  Reactions that form gases  Reactions that form water

30.  The formation of a solid precipitate can occur in some double displacement reactions  Precipitates are insoluble ionic compounds  Solubility of ionic compounds is determined using a solubility table

31. (c) McGraw Hill Ryerson 2007  When potassium chromate and silver nitrate react, they form a red precipitate, silver chromate, in a solution of potassium nitrate.  K 2 CrO 4 (aq) + 2AgNO 3 (aq)  Ag 2 CrO 4 (s) + 2KNO 3 (aq) silver chromate Two solutions react to form a precipitate (solid) and another solution. Ionic solution + ionic solution  ionic solution + ionic solid. AB + CD  AD + CB DOUBLE REPLACEMENT: http://www.youtube.com/watch?v=opY3FLrPTa4

32.  Once you write the molecular equation (synthesis, decomposition, etc.), you should check for reactants and products that are soluble or insoluble.  We usually assume the reaction is in water  We can use a solubility table to tell us what compounds dissolve in water.  If the compound is soluble (does dissolve in water), then splits the compound into its component ions  If the compound is insoluble (does NOT dissolve in water), then it remains as a compound

34.  Gases only slightly dissolve in water  Strong acids and bases dissolve in water  Hydrochloric, Hydrobromic, Hydroiodic, Nitric, Sulfuric, Perchloric Acids  Group I hydroxides (should be on your chart anyway)  Water slightly dissolves in water! (H+ and OH- )  For the homework… SrSO 4 is insoluble; BeI 2 and the products are soluble  There are other tables and rules that cover more compounds than your table!

35. Molecular Equation: K 2 CrO 4 + Pb(NO 3 ) 2  PbCrO 4 + 2 KNO 3 SolubleSolubleInsoluble Soluble Total Ionic Equation: 2 K + (aq) + CrO 4 2- (aq) + Pb 2+ (aq) + 2 NO 3 - (aq)  PbCrO 4 (s) + 2 K + (aq) + 2 NO 3 - (aq)

36.  These are the same as total ionic equations, but you should cancel out ions that appear on BOTH sides of the equation Total Ionic Equation: 2 K + + CrO 4 -2 + Pb +2 + 2 NO 3 -  PbCrO 4 (s) + 2 K + + 2 NO 3 - Net Ionic Equation: CrO 4 -2 + Pb +2  PbCrO 4 (s)

37.  Try this one! Write the molecular, total ionic, and net ionic equations for this reaction: Silver nitrate reacts with Lead (II) Chloride in hot water. Ionic Equation: Total Ionic: Net Ionic:

38. (c) McGraw Hill Ryerson 2007 Neutralization reactions occur when an acid (most compounds starting with H) and a base (most compounds ending in OH) react to form a salt and water. Acid + base  salt + water HOH HX + MOH  MX + H 2 O where X and M are elements HCl (aq) + NaOH (aq)  NaCl (aq) + H 2 O ( l ) See page 263

39. (c) McGraw Hill Ryerson 2007 1. Sulfuric acid is used to neutralize calcium hydroxide:  H 2 SO 4 + Ca(OH) 2  CaSO 4 + 2H 2 O 2. Phosphoric acid helps to neutralize the compounds that cause rust, such as iron(II) hydroxide.  H 3 PO 4 + 3Fe(OH) 2  Fe 3 (PO 4 ) 2 + 6H 2 O See page 263 NEUTRALIZATION: http://www.youtube.com/watch?v=_P5hGzA6Vb0

40. (c) McGraw Hill Ryerson 2007 After the double displacement reaction occurs, one of the products quickly decomposes into water and a gas If one of your products is carbonic acid (H 2 CO 3 (aq) ) it will decompose into CO 2 (g) and H 2 O ( l ) If one of your products is ammonium hydroxide (NH 4 OH (aq) ), it will decompose into NH 3 (g) and H 2 O (l) NaHCO 3 (aq) + HCH 3 COO (aq)  NaCH 3 COO + H 2 CO 3 H 2 CO 3 (aq)  CO 2 (g) + H 2 O ( l ) NH 4 Cl (aq) + NaOH (aq)  NH 4 OH (aq) + NaCl (aq) NH 4 OH (aq)  NH 3 (g) + H 2 O ( l ) See page 263

41. Predict the products. Balance the equation 1. HCl (aq) + AgNO 3(aq)  2. CaCl 2(aq) + Na 3 PO 4(aq)  3. Pb(NO 3 ) 2(aq) + BaCl 2(aq)  4. FeCl 3(aq) + NaOH (aq)  5. H 2 SO 4(aq) + NaOH (aq)  6. KOH (aq) + CuSO 4(aq) 

42. Combustion reactions occur when a hydrocarbon reacts with oxygen gas. This is also called burning!!! In order to burn something you need the 3 things in the “fire triangle”: 1) A Fuel (hydrocarbon) 2) Oxygen to burn it with 3) Something to ignite the reaction (spark)

43. In general: C x H y + O 2  CO 2 + H 2 O Products in combustion are ALWAYS carbon dioxide and water. (although incomplete burning does cause some by- products like carbon monoxide) Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C 8 H 18 )

44. (c) McGraw Hill Ryerson 2007 1. Natural gas (methane) is burned in furnaces to heat homes.  CH 4 + O 2  CO 2 + 2H 2 O + energy 2. An acetylene torch is used to weld metals together.  2C 2 H 2 + 5O 2  4CO 2 + 2H 2 O + energy 3. Carbohydrates like glucose combine with oxygen in our body to release energy.  C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy See page 264 Acetylene torch

45. Edgar Allen Poe’s drooping eyes and mouth are potential signs of CO poisoning.

46. Example C 5 H 12 + O 2  CO 2 + H 2 O Write the products and balance the following combustion reaction: C 10 H 22 + O 2  5 6 8

47. State the type, predict the products, and balance the following reactions: 1. BaCl 2 + H 2 SO 4  2. C 6 H 12 + O 2  3. Zn + CuSO 4  4. Cs + Br 2  5. FeCO 3 