1. Chapter 10 Chemical Reactions

2. 2 Homework for Chap 10 Read p 251 – 263; 265 - 268 Applying the Concepts # 1 – 34, 36 – 39, 43 – 44, 46 - 49

3. 3 Molecular formula ≡ actual number of atoms of each element in a molecule Empirical formula ≡ simplest whole-number ratio of the atoms in a substance H2OH2O H2OH2O molecularempirical C 6 H 12 O 6 CH 2 O O3O3 O N2H4N2H4 NH 2 Chemical Formulas

4. Fig 10.2 Several ways to express common molecules

5. 3 ways of representing the reaction of H 2 with O 2 to form H 2 O Chemical reaction ≡ process in which one or more substances is changed into one or more new substances Chemical equation ≡ use of chemical symbols to show what happens during a chemical reaction reactantsproducts

6. Fig 10.4 The Combustion of Charcoal C + O 2 → CO 2 “Carbon reacts with oxygen to yield carbon dioxide”

7. Fig 10.5 The meaning of subscripts and coefficients

8. Fig 10.6 Illustration of the Law of Conservation of Mass

9. Fig 10.7 Combustion of propane C 3 H 8 + O 2 → CO 2 + H 2 O C 3 H 8 + 5 O 2 → 3 CO 2 + 4 H 2 O

10. Fig 10.8 Hydrocarbons and Carbohydrates C 8 H 18 C3H8C3H8 C 12 H 22 O 11 Combustion of any hydrocarbon → CO 2 + H 2 O

11. 11 Types of Chemical Reactions 1)Oxidation-Reduction (Redox) 2) Combination 3) Decomposition 4) Replacement 5) Ion Exchange

12. Oxidation-Reduction Reactions (electron transfer reactions) 2 Mg (s) + O 2 (g) 2 MgO (s) Mg is the reducing agent (supplies electrons and is oxidized) O 2 is the oxidizing agent (takes electrons and is reduced) Oxidation – an atom loses electrons Reduction – an atom gains electrons Mg 2+ O 2- Oil Rig

13. Fig 10.9 Example of an oxidizing agent (“chlorine”) Others: Bleach Hydrogen peroxide Oxygen Ultraviolet light

14. 14 Types of Chemical Reactions 1)Oxidation-Reduction (Redox) 2) Combination 3) Decomposition 4) Replacement 5) Ion Exchange

15. Fig 10.10 Iron combines with oxygen to form rust (iron oxide) 4 Fe (s) + 3 O 2 (g) 2 Fe 2 O 3 (s)

16. Hydrogen combines with oxygen to form water (dihydrogen monoxide)

17. 17 Types of Chemical Reactions 1)Oxidation-Reduction (Redox) 2) Combination 3) Decomposition 4) Replacement 5) Ion Exchange

18. F IG. 10.11 D ECOMPOSITION OF M ERCURY O XIDE 2 HgO (s) → 2 Hg (l) + O 2 (g) Δ HgO Hg

19. Decomposition of Hydrogen Peroxide 2 H 2 O 2 (l) → 2 H 2 O (l) + O 2 (g)

20. 20 Types of Chemical Reactions 1)Oxidation-Reduction (Redox) 2) Combination 3) Decomposition 4) Replacement 5) Ion Exchange

21. 2 Al (s) 3 CuCl 2 (aq) → 2 AlCl 3 (aq) + 3 Cu (s) CuCl 2 Cu Al AlCl 3 Fig 10.13 Replacement reaction between aluminum metal and the blue copper chloride solution

22. Replacement reactions take place when Replacement reactions take place when a more active metal gives up electrons to a less active metal. How do we know if a replacement reaction How do we know if a replacement reaction will take place or not occur? Refer to the activity series for common metals Refer to the activity series for common metals Fig 10.12, p 262 Fig 10.12, p 262

23. Fig 10.12 The activity series for common metals

24. 2 Na + 2H 2 O 2NaOH + H 2 ↑ Zn + 2HCl ZnCl 2 + H 2 ↑ Cu + HCl no reaction