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What is produced in a combustion reaction?

CHEMISTRY 8-22-08 Fri (per 1,2,3) WARM-UP: What is produced in a combustion reaction? LG: Become familiar with formulas, subscripts, equations & energy changes. TODAY’S AGENDA: TURN IN YOUR ESSAY & CONTRACT 1) What Chemical Is It? 2) Ira Remsen Demonstration HW: Sec 8.2—Read & take notes. .

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What is produced in a combustion reaction?

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  1. CHEMISTRY 8-22-08 Fri (per 1,2,3)WARM-UP:What is produced in a combustion reaction?LG: Become familiar with formulas, subscripts, equations & energy changes.TODAY’S AGENDA:TURN IN YOUR ESSAY & CONTRACT1) What Chemical Is It?2) Ira Remsen DemonstrationHW: Sec 8.2—Read & take notes.

  2. What is produced in a combustion reaction? Carbon dioxide (CO2) & water (H2O)

  3. What chemical is it?

  4. C6H12O6 (s) formula chemical symbol (the letter) subscript (the number) state symbol

  5. ring stand round bottom flask iron ring pre-1982 penny clamp rubber stopper tubing graduated cylinder Ira Remsen Demonstration Diagram

  6. To be read during the reaction: • While reading a textbook of chemistry I came upon the statement, "nitric acid acts upon copper." I was getting tired of reading such absurd stuff and I was determined to see what this meant. Copper was more or less familiar to me, for copper cents were then in use. I had seen a bottle marked nitric acid on a table in the doctor's office where I was then "doing time." I did not know its pecularities, but the spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words "act upon" meant. The statement "nitric acid acts upon copper" would be more than mere words.

  7. To be read during the reaction: • All was still. In the interest of knowledge I was even willing to sacrifice one of the few copper cents then in my possession. I put one of them on the table, opened the bottle marked nitric acid, poured some of the liquid on the copper and prepared to make an observation. But what was this wonderful thing which I beheld? The cent was already changed and it was no small change either. A green-blue liquid foamed and fumed over the cent and over the table. The air in the neighborhood of the performance became colored dark red. A great colored cloud arose. This was disagreeable and suffocating. How should I stop this?

  8. To be read during the reaction: • I tried to get rid of the objectionable mess by picking it up and throwing it out of the window. I learned another fact. Nitric acid not only acts upon copper, but it acts upon fingers. The pain led to another unpremeditated experiment. I drew my fingers across my trousers and another fact was discovered. Nitric acid acts upon trousers. Taking everything into consideration, that was the most impressive experiment and relatively probably the most costly experiment I have ever performed... It was a revelation to me. It resulted in a desire on my part to learn more about that remarkable kind of action. Plainly, the only way to learn about it was to see its results, to experiment, to work in a laboratory.

  9. Equation for the reaction: Cu(s) + HNO3(aq)  NO2(g) + H2O(l) + Cu(NO3)2(aq) reactants  products Copper + nitric acid produces nitrogen + water + copper(II)nitrate dioxide things on the left  things on the right

  10. State symbols • “s” = solid • “l” = liquid • “g” = gas • “aq” = aqueous (dissolved in water)

  11. Energy changes • Because heat is released in this reaction it is called an “exothermic” reaction.

  12. Why does the penny have to be “old”? • Pre-1982 pennies are mostly copper. • Post-1982 pennies are made up of a zinc core surrounded by a thin layer of copper.

  13. Chemistry of Color • The NO2 gas produced is brown—ALL COLORED GASES ARE POISONOUS. • Copper ions tend to produce blue solutions.

  14. CHEMISTRY 8-22-08 Fri (per 6,7)WARM-UP:How do you use a fire extinguisher, dispose of glass, treat spills?LG: Learn about energy changes & bonds. Use the scientific method in the lab.TODAY’S AGENDA: PRIZES!1) Evaluate notes; take Sec. 8.2 quiz.2) Finish Ira Remsen notes.3) Anchor overboard activity.HW: Sec. 1.3—Read & take notes; NOTE THE CHANGE!!

  15. Equation for the reaction: Cu(s) + HNO3(aq)  NO2(g) + H2O(l) + Cu(NO3)2(aq) reactants  products Copper + nitric acid produces nitrogen + water + copper(II)nitrate dioxide things on the left  things on the right

  16. State symbols • “s” = solid • “l” = liquid • “g” = gas • “aq” = aqueous (dissolved in water)

  17. Energy changes • Because heat is released in this reaction it is called an “exothermic” reaction. • Energy is involved when bonds between atoms are broken and formed.

  18. Why does the penny have to be “old”? • Pre-1982 pennies are mostly copper. • Post-1982 pennies are made up of a zinc core surrounded by a thin layer of copper.

  19. Chemistry of Color • The NO2 gas produced is brown—ALL COLORED GASES ARE POISONOUS. • Copper ions tend to produce blue solutions.

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