2. Catalyst – November 9+2 3, 2009 What are the four ways you know a chemical reaction has occurred? Balance:. __Ca + __H 2 O  __Ca(OH) 2 + __H 2 Weekly Goal!

3. Today’s Agenda  Catalyst  Chemistry Prom 2009 Day 1!  Practice and Work Time  Exit Question

4. Today’s Objectives  SWBAT differentiate between combustion, synthesis, and decomposition reactions.  SWBAT predict the products of combustion, synthesis, and decomposition reactions.

5. Is this an example of a chemical reaction? How do you know?

6. Evidence of Chemical Reactions 1. Formation of a gas 2. Formation of a precipitate 3. Temperature change 4. Color change

7. Questions from Friday  SCENARIO: Juan wanted to see what would happen if he mixed water and salt together. After adding the salt and stirring, he observed that the salt seemed to disappear.  QUESTION: Did a chemical reaction occur?

8. Questions from Friday  SCENARIO: Jayde is interested in learning about two compounds, silver (I) nitrate and sodium chloride. She decides to dissolve each compound in water and mix them. When she does this, she sees a white solid form.  QUESTION: Did a chemical reaction occur?

9. Questions from Friday  SCENARIO: Antoinette puts 2 grams of salt into a beaker filled with a clear unknown liquid. The salt appears to disappear into the liquid.  QUESTION: Did a chemical reaction occur?

10. Questions from Friday  SCENARIO: William was curious about what would happen if he mixed zinc and hydrochloric acid. After doing so, the mixture bubbles and fizzes.  QUESTION: Did a chemical reaction occur?

11. Combustion, Synthesis, and Decomposition Reactions

13. Chemical Reactions  There are 5 types of chemical hook- ups (reactions) at the prom this year. 1. Combustion 2. Synthesis 3. Decomposition 4. Single-Replacement 5. Double-Replacement

14. Boom goes the dynamite! Key Point #1: A combustion reaction is when a hydrocarbon burns in the presence of oxygen, releasing heat and light  The products will ALWAYS be CO 2 and H 2 O A hydrocarbon is any compound made of only hydrogen and carbon Ex: CH 4, C 2 H 4 Is C 50 H 102 a hydrocarbon?

15. Combustion Examples Predict products and balance 1. CH 4 (g) + O 2 (g)  2. C 2 H 2 (g) + O 2 (g)  CO 2 (g) + 2 H 2 O(g) 4 CO 2 (g) + 2 H 2 O(g) 2 5 2

16. Practice  Write the chemical reaction for ethane gas (C 2 H 6 ) burning in air. 1. If you see the word “BURNING,” that means it is a combustion reaction. 2. What are the reactants? C 2 H 6 and O 2 3. What are the products? CO 2 and H 2 O 4. Last step: Balance! (don’t worry about phases for now) C 2 H 6 + O 2  CO 2 + H 2 O

17. Your Turn!  Write balanced equations for the following reactions: 1. Methane gas (CH 4 ) combusts. 2. Butene gas (C 4 H 4 ) burns in the air. 3. Ethyne gas (C 2 H 2 ) goes through a combustion reaction.

18. Let’s come together Key Point #2: A synthesis reaction is one in which two or more substances combine to form one new substance.  A + B  AB  Two substances are at the Prom, dancing alone…they decide to hook up…

19. Let’s come together….  Synthesis reaction – two more substances combine to form one new substance.  Two substances dancing alone decide to hook up… become a happy couple  A + B  AB Man I’m lonely Geez I could use a mate. Satisfaction

20. Practice  Show the synthesis of solid aluminum and oxygen gas.  What are the reactants? Al + O 2 (DIATOMIC ALERT!!!!)  What are the products? It’s a synthesis reaction, so we know Al and O are going to make a compound…. If the products aren’t in the question you need to KRISS KROSS TO figure them out! Al (s) + O 2 (g)  AlOAl 3+ O 2- Al 2 O 3

21. Practice  Which reactions are synthesis reactions? A. C + O 2  CO 2 B. CaO + H 2 O  Ca(OH) 2 C. H 2 O  H 2 + O 2 D. 2Na + Cl 2  2NaCl E. Fe + CuSO 4  FeSO 4 + Cu F. 2K 3 PO 4 + 3H 2 SO 4  3K 2 SO 4 + 2H 3 PO 4 A, B, and D

22. I don’t think this is working out… Key Point #3: A decomposition reaction is one in which one substance breaks down into multiple substances, usually with the help of some kind of heat or energy  AB  A + B  A couple at the Prom decides to break up

23. I don’t think this is working out…  Decomposition reaction – one substance breaks into multiple substances  A couple decides…well it is time to break up  AB  A + B I don’t think this is right for us… I want to see other people Satisfaction!

24. Practice  Show the decomposition water after electricity has passed through it.  What are the reactants? Water! H 2 O  What are the products? It’s a decomposition reaction, so we know the elements in water are going to break apart The question will specify if any compounds are formed H 2 O  H + O Diatomic Alert!!!! H 2 + O 2 Don’t forget to balance!

25. Practice – Your Turn! 1. Show the decomposition of ammonium nitrate into dinitrogen monoxide and water when the reactant is heated. 2. Show the decomposition of NaN 3.

26. More Practice!  Which reactions are decomposition reactions? A. C + O 2  CO 2 B. CaO + H 2 O  Ca(OH) 2 C. H 2 O  H 2 + O 2 D. H 2 SO 4  H 2 + S + 2O 2 E. Fe + CuSO 4  FeSO 4 + Cu F. K 3 PO 4  K 3 P + 2O 2 C, D and F

27. Work Time – 3 Parts A) Write one word problem and balanced chemical equation for each type of reaction (combustion, synthesis, decomposition)  Examples of Hydrocarbons: Propane (C 3 H 8 ), Propene (C 3 H 4 ), Propyne (C 3 H 2 ) Pentane (C 5 H 12 ), Pentene (C 5 H 10 ), Pentyne (C 5 H 8 ) B) Book work: Pg 285, 14-20 C) Early Finishers: Predict what the chemical formulas for Octene and Octyne would be. Octane is C 8 H 18.

28. Part A Examples  Combustion  Word Problem: Carbon tetrahydride reacts with oxygen gas to produce carbon dioxide and water.  Balanced Equation: CH 4 + 2 O 2  CO 2 + 2 H 2 O  Synthesis  Word Problem: Hydrogen and oxygen react to form water.  Balanced Equation: H 2 + O 2  H 2 O  Decomposition  Word Problem: Water decomposes to form hydrogen and oxygen.  Balanced Equation: H 2 O  H 2 + O 2

29. Exit Question 1. Identify the following reactions as combustion, synthesis, or decomposition  CH 4 + 2 O 2  CO 2 +2 H 2 O  2 H 2 NO 3  2 H 2 + N 2 + 3 O 2 2. Write the balanced chemical equation for the decomposition of solid magnesium oxide.