Compounds and Chemical Reactions

1. Compounds and Chemical Reactions

2. Compounds • Compounds: Pure substances that are made from two or more types of atoms chemically bonded together • Have chemical formulas • Can only be separated by chemical means • (Not to be confused with molecules) • Molecules: two or more atoms chemically bonded together (can be elements or compounds)

3. Formation of Compounds • Formed by chemical bonds between elements • Bonding involves only the valenceelectrons • # of valence electrons determined by the group # Na Cl

4. Group 1 Group 18 Group 2 Group 13 Group 14 Group 15 Group 16 Group 17

5. Octet Rule Octet Rule = atoms tend to gain, lose, or share electrons to have 8 valence electrons ⏎ Share 2 electrons

6. Types of Chemical Bonds • Two types of chemical bonds: • Ionic bonds • Covalent bonds

7. Covalent Bonds • Covalent Bond: sharing of electrons between elements in a compound • Made between non-metals

8. Ionic Bonds • Ionic Bond: transferring of electrons between elements in a compound; forms ions • Made between a metal and a non-metal

9. Ionic Bonds cont... • Ions: a charged atom; due to losing or gaining of electrons (ex. Na+, O-2) • Depends on valence electrons • Positive = electrons are lost • Negative = electrons are gained • example: Oxygen has 6 valence electrons and will gain two electrons to form an Octet • C would like to • N would like to • Na would like to Gain 4 electrons Gain 3 electrons Lose 1 electrons

10. Ionic Bonds cont...

11. Learning Check A. Number of valence electrons in aluminum 1) 1 e- 2) 2 e- 3) 3 e- B. Change in electrons for octet 1) lose 3e- 2) gain 3 e- 3) gain 5 e- C. Ionic charge of aluminum 1) 3- 2) 5- 3) 3+

12. Solution A. Number of valence electrons in aluminum 3) 3 e- B. Change in electrons for octet 1) lose 3e- C. Ionic charge of aluminum 3) 3+

13. Chemical Reactions • Chemical Reaction: happens when bonds are made or broken • Causes chemical changes in the matter involved ex. Na (metal highly reactive with water) + Cl2(poisonous gas)  NaCL: something delicious

14. Reminder: Signs of a Chemical Reaction

15. Chemical Equations • Chemical Equations: used to show chemical reactions and how much of each reactant and product are needed • Reactants: substance(s) at the beginning of the reaction (left side of arrow) • Products: substance(s) at the end of the reaction (right side of arrow)

16. Chemical Equations Coefficients: numbers in front of the reactants and products that tell how many are needed 4Al (s)+3O2 (g) ---> 2Al2O3 (s) Reactants Products

17. Types of Reaction Equations • There are two types of chemical reaction equations: WordandFormulaequations • Formula Equation Example: • C(g) + O2(g) CO2(g) • Word Equation Example: • Carbon gas plus oxygen gas react to yield carbon dioxide gas

18. Symbols Used in Equations • + and or plus •  yields • (s) solid • (l) liquid • (g) gas • (aq) aqueous solution • H2SO4catalyst • heat added

19. Energy of Reactions Reactions can give off heat energy or absorb heat energy Exothermic: Give off energy (exo: exit) ex. Cellular Respiration 6 CO2 + 6 H2O  C6H12O6 + ATP energy Endothermic: Absorbs energy (endo: in) ex. Photosynthesis C6H12O6 + sunlight  6 CO2 + 6 H2O

20. 5 Main types of reactions Synthesis aka“Love at first sight” A + B  AB • Decomposition aka “The big break-up” • AB  A + B • Single Replacement aka “My best friend’s girlfriend” • AB + C  CB + A • Double Replacement aka “Revenge” • AB + CD  AD + CB • Combustion aka “The Playa” • AB + O  AO + BO

21. Classification of Chemical Reactions: The Soap-Opera of Chemistry

22. Synthesis- “Love at first sight” I like your hat Hey Harry Can I get your number? I like your braces! Hey Sally Basic equation: A+B --> AB

23. Synthesis- “Love at first sight” • The compound produced is larger and more complex than the reactants • Element/compound + Element/Compound = Large Compound • Example: H2 + O2 ---> H2O

24. Decomposition- “The Big Break-up” I was washing my hair. Whatever! We are through! Where were you last night? I don’t believe you I’m leaving! But, baby I love you! • Basic Equation: AB --> A+B

25. Decomposition- “The Big Break-up” I am so over you • The Breakdown of a larger compound • Example: 2 H2O --> 2 H2 + O2

26. Single Replacement- “My Best Friend’s Girlfriend” This Sucks! Hey Mark, here comes your friend Pierre! Oh Pierre! Mark I’m leaving you! Hey, Baby. How you doing? Man, Mark’s Girl is pretty HOTT! Basic Equation: AX + B --> BX + A

27. Single Replacement- “My Best Friends Girlfriend” • “Free” element must be the more reactive element for a reaction to occur ( Pierre is more suave then Mark) • Cations always replaces cations and anions always replace anions • Example: 2K + 2HCl --> 2KCl + H2 • (K is more reactive than H)

28. Double Replacement- “Revenge” Chloe was my one true love, but Mark’s girl is looking pretty HOTT! I can’t believe Chloe would do that! I have to get Pierre back. Hey Chloe do you want to go out? But Chloe I love you, I can’t live with out you!!! Of course! Hey Baby Pierre, I’m so sick of you! Oh Pierre! Basic Equation: AX + BY --> AY + BX

29. Double Replacement- “Revenge” • One element in each compound switches places with the other element in the other compound • Always involves the formation of a molecular compound such as water (Tears) and either a precipitate or a gas • Example: 2 KI(aq) + Pb(NO3)2(aq)--> PbI2(s) + 2 KNO3(aq)

30. Combustion- “The playa” That was a great date! Who’s that HOTTIE? Ashley you’re my BFF!! Hey Ladies!! How you doin? Baby, I love you! (3 weeks later) BLING! Basic Equation: AB + O --> AO + BO

31. Combustion- “The player” Honey, Why is Ashley’s number on your phone? • Oxygen is the playa • Produce oxide compounds and energy (very exothermic) • Example: CH4 + 2O2--> CO2 + 2H2O + ENERGY

32. Your Assignment Create a Reaction Comic Book Must Contain all 5 types of reactions and have pictures and captions Must include name of reaction and a real example Needs to include color Does not have to be hand drawn

33. Example I need to focus on my rapping baby WESH.com Decomposition