Hewitt/Lyons/Suchocki/Yeh Conceptual Integrated Science

1. Hewitt/Lyons/Suchocki/YehConceptual Integrated Science Chapter 13 CHEMICAL REACTIONS

2. This lecture will help you understand: • Chemical Reactions and Equations • Acid–Base Reactions • Salts • Solutions: Acidic, Basic, or Neutral • The pH Scale • Oxidation-Reduction Reactions • Corrosion and Combustion • Reaction Rates • Exo- and Endothermic Reactions • Entropy and Chemical Reactions

3. Chemical Reactions and Equations During a chemical reaction, one or more new compounds are formed as a result of the rearrangement of atoms. Reactants Products

4. Chemical Reactions and Equations Law of Mass Conservation: No atoms are gained or lost during any reaction.

5. Chemical Reactions and Equations Law of Mass Conservation: No atoms are gained or lost during any reaction. The number of times atoms appear before the arrow must be equal to the number of times they appear after the arrow.

6. Chemical Reactions and Equations CHECK YOUR NEIGHBOR In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12

7. Chemical Reactions and Equations CHECK YOUR ANSWER In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12 Explanation: The atoms of the reactants are the SAME atoms of the products, except in a different configuration.

8. Chemical Reactions and Equations CHECK YOUR ANSWER In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12 reactants Explanation: The atoms of the reactants are the SAME atoms of the products, except in a different configuration.

9. Chemical Reactions and Equations CHECK YOUR ANSWER In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12 reactants Explanation: The atoms of the reactants are the SAME atoms of the products, except in a different configuration.

10. Chemical Reactions and Equations CHECK YOUR ANSWER In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12 reactants Explanation: The atoms of the reactants are the SAME atoms of the products, except in a different configuration.

11. Chemical Reactions and Equations CHECK YOUR ANSWER In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12 reactants Explanation: The atoms of the reactants are the SAME atoms of the products, except in a different configuration.

12. Chemical Reactions and Equations CHECK YOUR ANSWER In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12 products Explanation: The atoms of the reactants are the SAME atoms of the products, except in a different configuration.

13. Chemical Reactions and Equations CHECK YOUR ANSWER In total, how many atoms are represented by the following schematic for a chemical reaction? A. 2 • 5 • 6 • 12 products products “conventional” equation format All you see here are six different atoms!

14. Chemical Reactions and Equations CHECK YOUR NEIGHBOR Is this reaction balanced? A. Yes • No

15. Chemical Reactions and Equations CHECK YOUR ANSWER Is this reaction balanced? A. Yes • No

16. Chemical Reactions and Equations CHECK YOUR NEIGHBOR How many “diatomic” molecules are represented? A. 1 • 2 • 3 • 4

17. Chemical Reactions and Equations CHECK YOUR ANSWER How many “diatomic” molecules are represented? A. 1 • 2 • 3 • 4 before after Explanation: The diatomic molecule shown with the products is actually the same molecule shown to the left with the reactants. What happened here is that this molecule didn’t react.

18. Chemical Reactions and Equations CHECK YOUR ANSWER How many “diatomic” molecules are represented? A. 1 • 2 • 3 • 4 before after Explanation: The diatomic molecule shown with the products is actually the same molecule shown to the left with the reactants. What happened here is that this molecule didn’t react.

19. Chemical Reactions and Equations CHECK YOUR NEIGHBOR Is the following chemical equation balanced? A. No, because the molecules have changed. • Yes, because the coefficients on each side add up to the same number. • No, because there are more oxygen atoms in the products. • Yes, because the same atoms appear before and after. 1 CH4 + 2 O2 2 H2O + 1 CO2

20. Chemical Reactions and Equations CHECK YOUR ANSWER Is the following chemical equation balanced? A. No, because the molecules have changed. • Yes, because the coefficients on each side add up to the same number. • No, because there are more oxygen atoms in the products. • Yes, because the same atoms appear before and after. 1 CH4 + 2 O2 2 H2O + 1 CO2

21. Acid–Base Reactions

22. Acid–Base Reactions

23. Acid–Base Reactions Acid • A chemical that donates a hydrogen ion, H+ Base • A chemical that accepts a hydrogen ion, H+

24. The hydrogen atom H

25. The hydrogen atom H

26. The hydrogen atom H

27. The hydrogen atom H

28. The hydrogen atom H

29. The hydrogen atom H

30. The hydrogen atom H

31. The hydrogen ion H+

32. The hydrogen ion H+

33. The hydrogen ion H+

34. The hydrogen ion H+

35. The hydrogen ion H+

36. The hydrogen ion H+

37. The hydrogen ion H+

38. The hydrogen ion H+

39. The hydrogen ion H+ proton

40. Base Accepts Acid Donates

41. HCl H2O +

42. HCl H2O +

43. Cl– H3O+ +

44. HCl H2O Cl– H3O+ + +

45. HCl H2O Cl– H3O+ + +

46. HCl H2O Cl– H3O+ + + donor acceptor

47. HCl H2O Cl– H3O+ + + (acid) (base)

48. H2O NH3 +

49. H2O NH3 +

50. OH– NH4+ +