1. CHEMICAL BONDS CHAP 9

2. 2 For Science Fair Judges Write a 1 – 2 page word-processed report evaluating 2 projects. If you are not a judge, you may submit this assignment for 15 extra- credit points or as a lab make-up.

3. 3 Composition of Ionic Compounds Common names: “salt” → sodium chloride “lye” → sodium hydroxide “rust” → iron oxide “baking soda” → sodium bicarbonate “chalk” → calcium carbonate

4. Fig. 9.12 Three substances containing sodium and some form of the carbonate ion

5. 5 Names for Ionic Compounds containing only two different elements Metal (positive) ion is written and spoken first Negative element is written/spoken second Subscripts used to produce an electrically neutral compound e.g. NaCl, CaO, KI, Fe 2 O 3, CaC 2

6. Fig 11.6 NaCl dissolving in water

7. Box Fig. 9.1 Conductivity tester for determining if a solution contains ions Fact: Dissolving an ionic compound in water results in ions being pulled apart from the crystal lattice to form free ions +−

8. Chapter 10 Chemical Reactions

9. 9 Homework for Chap 10 Read p 253 – 257; 261 - 271 Applying the Concepts # 1 – 17

10. 10 A molecular formula shows the actual number of atoms of each element in the smallest unit of a substance An empirical formula shows the 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

11. Fig. 10.2 Several ways to express common molecules

12. 3 ways of representing the reaction of H 2 with O 2 to form H 2 O A process in which one or more substances is changed into one or more new substances is a chemical reaction A chemical equation uses chemical symbols to show what happens during a chemical reaction reactantsproducts

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

14. Fig. 10.5 The meaning of subscripts and coefficients

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

16. Fig. 10.8 Hydrocarbons and Carbohydrates C 8 H 18 C3H8C3H8 C 12 H 22 O 11

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

18. 18 Oxidation-Reduction Reactions (electron transfer reactions) 2Mg (s) + O 2 (g) 2MgO (s) Mg is the reducing agent (supplies electrons) O 2 is the oxidizing agent (takes electrons) Oxidation – an atom loses electrons Reduction – an atom gains electrons

19. Fig. 10.9 Example of an oxidizing agent (“chlorine”) Others: 1) Bleach 2) Hydrogen peroxide 3) Oxygen 4) Ultraviolet light

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

21. 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)

22. 22 Types of Chemical Reactions 1) 1)Oxidation-Reduction (Redox) 2) 2) Combination 3) 3) Decomposition 4) 4) Replacement 5) 5) Ion Exchange

23. Fig. 10.11 Decomposition of Mercury Oxide 2 HgO (s) → 2 Hg (l) + O 2 (g) heat