Introduction to Chemical Reactions

1
Introduction to Chemical Reactions

• Learning Reaction Types and Their Patterns

2
Synthesis

• A B ? AB
• Element A Element B ? Compound AB
• Magnesium Strip Oxygen Gas ? Solid Magnesium
  Oxide

3

• 2 Mg(s) O2 (g) ? 2 MgO (s) (white powder)

4
Decomposition

• AB ? A B
• Compound AB ? Element A Element B
• Aqueous hydrogen peroxide ? oxygen gas liquid
  water

5
Splint Test

• A test used to determine the production of one of
  the following gases
• O2 flame gets bigger and splint will relight
• CO2 flame will go out
• H2 popping noise
• (flame may go out from mini explosion!)

6

• 2 H2O2 (aq) ? O2 (g) 2 H2O (l)

7

• ABCD ? AB C D
• Compound ABCD ? Compound AB
  Element C Element D
• Solid ammonium dichromate ? solid chromium (III)
  oxide nitrogen gas water vapor

8

• ABCD ? AB C D
• Compound ABCD ? Compound AB
  Element C Element D
• Solid ammonium dichromate ? solid chromium (III)
  oxide nitrogen gas water vapor

9

• (NH4)2Cr2O7 (s) ? N2 (g) Cr2O3 (s) 4 H2O (g)

10
Single Replacement - Cationic

• A BC ? B AC
• Element A Compound BC? Element B Compound AC
• Note Elements A B are metals
• Copper wire aqueous silver nitrate ? solid
  silver aqueous copper (I) nitrate

11

• Cu(s) AgNO3 (aq) ? Ag(s) CuNO3 (aq) (blue)

12

• Iron nail copper (II) chloride solution ? solid
  copper iron (II) chloride solution

13

• Fe(s) CuCl2 (aq) ? FeCl2 (aq) Cu (s) (red)

14

• Solid zinc aqueous hydrochloric acid ? hydrogen
  gas aqueous zinc chloride

15

• Zn(s) 2HCl(aq) ? ZnCl2 (aq) H2 (g) (pop
  splint test)

16
Single Replacement - Anionic

• A BC ? C BA
• Element A Compound BC ? Element C Compound BA
• Note Elements A C are nonmetals

17

• Chlorine gas aluminum bromide solution ?
  bromine gas aluminum chloride solution

18

• 3Cl2 (g) 2AlBr3 (aq) ? 3Br2 (g) 2AlCl3 (aq)

19
Double Replacement

• AB CD ? AD CB
• Compound AB Compound CD ? Compound AD
  Compound BC
• aqueous copper (II) nitrate aqueous sodium
  hydroxide ? copper (II) hydroxide (ppt) aqueous
  sodium nitrate.

20

• Cu (NO3)2 (aq) 2 NaOH (aq) ? Cu (OH)2 (s) 2
  NaNO3 (aq)

21

• aqueous silver nitrate potassium chromate ?
  aqueous potassium nitrate solid silver chromate

22

• AgNO3 (aq) K2CrO4 (aq) ? KNO3 (aq) Ag2CrO4
  (s)

23

• In order for a double replacement reaction to
  occur, one of the following must be produced
• Gas
• Water
• Precipitate (ppt.)

24
Precipitation Animation

• http//www.mhhe.com/physsci/chemistry/animations/c
  hang_7e_esp/crm3s2_3.swf

25
Combustion

• Hydrocarbon oxygen ? carbon dioxide water
  heat
• Hydrocarbon is a compound containing carbon,
  hydrogen and sometimes oxygen (CxHyOz)
• aqueous methanol oxygen gas ? carbon dioxide
  gas liquid water

26

• 2 CH3OH(aq) 3 O2 (g) ? 2 CO2 (g)
• 4 H2O (l) heat

27

• methane gas oxygen gas ? carbon dioxide gas
  water vapor

28

• CH4 (g) 2O2 (g) ? CO2 (g) 2H2O(g)