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Smells Unit

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  1. Smells Unit Investigation II: Picturing Molecules Lesson 1: Molecules in Two Dimensions Lesson 2: Honk If You Like Molecules Lesson 3: Connect the Dots Lesson 4: Eight is Enough Lesson 5: Dots, Dots, and More Dots Lesson 6: Where’s the Fun? Lesson 7: Create a Smell Lesson 8: Making Scents

  2. Smells Unit – Investigation II Lesson 1: Molecules in Two Dimensions

  3. Molecule #2 Molecule #1 ChemCatalyst • Here are drawings of two molecules that you’ve already smelled. List at least three differences and three similarities between the two molecules. Unit 2 • Investigation II

  4. The Big Question • Can the structural formula of a molecule help us to predict how it will smell? Unit 2 • Investigation II

  5. You will be able to: • Describe a molecule based on its smell. Unit 2 • Investigation II

  6. Notes • A structural formula is a drawing or diagram that a chemist uses to show how the atoms in a molecule are connected. • Chemists refer to the connections between atoms in a molecule as a bond. In structural formulas, the covalent bonds are represented as lines. Unit 2 • Investigation II

  7. Activity • Purpose: In this lesson you are introduced to the structural formulas of the molecules you have smelled plus some new molecules. You will look for patterns in the ways the atoms are connected. Unit 2 • Investigation II

  8. Making Sense • What structural features seem to be the best predictors of the smell of a molecule? Unit 2 • Investigation II

  9. carboxylic acid ketone ester amine Notes (cont.) Unit 2 • Investigation II

  10. Notes(cont.) • Functional groups are structural features that show up repeatedly in molecules and seem to account for some of their chemical properties. (cont.) Unit 2 • Investigation II

  11. ketone functional group carboxylic acid functional group ester functional group amine functional group Notes(cont.) Unit 2 • Investigation II

  12. Check-In • If a molecule is sweet, what other things do you know about it? List at least four things that are probably true. Unit 2 • Investigation II

  13. Wrap-Up • Structural formulas show how the atoms in a molecule are put together. • Certain structural features in molecules called functional groups appear to be related to smell. Unit 2 • Investigation II

  14. Smells Unit – Investigation II Lesson 2: Honk If You Like Molecules

  15. Molecule K diisobutylamine fishy Molecule E menthone minty ChemCatalyst • Examine the following molecules. What patterns do you see in the bonding of hydrogen, oxygen, carbon, and nitrogen? Unit 2 • Investigation II

  16. The Big Question • How can HONC 1234 help us to draw structural formulas? Unit 2 • Investigation II

  17. You will be able to: • Determine whether the structural formula of a given molecule is possible. Unit 2 • Investigation II

  18. Notes • HONC 1234 is a simple, catchy phrase reminding us about the bonding of hydrogen, oxygen, nitrogen and carbon. This easy-to-remember phrase reminds us how many bonds each element usually makes within a molecule. (cont.) Unit 2 • Investigation II

  19. Notes(cont.) • Double bonds and triple bonds still follow the HONC 1234 rule. The double-bonded oxygen in the menthone molecule is bonded twice to carbon and therefore follows the guidelines. Unit 2 • Investigation II

  20. Activity • Purpose: The purpose of this activity is to give you practice in creating structural formulas from molecular formulas and to help you begin to understand why atoms end up in the specific arrangements we find them in. (cont.) Unit 2 • Investigation II

  21. (cont.) • Molecular formula #1 — C3H8 • Molecular formula #2 — C3H8O • Molecular formula #3 — C3H9N Unit 2 • Investigation II

  22. Making Sense • The third molecular formula has at least three possible structures. Are these all the same molecule? Explain. Unit 2 • Investigation II

  23. Notes • Molecular formula #1 (the same molecule drawn with two different orientations) (cont.) Unit 2 • Investigation II

  24. Notes(cont.) • Molecular formula #2 (four different drawings are shown – three different molecules are represented) (cont.) Unit 2 • Investigation II

  25. Notes(cont.) • Molecular formula #3 (four different drawings are shown – however, they represent only three different structures) (cont.) Unit 2 • Investigation II

  26. Notes(cont.) • Molecules are isomers of one another if they have the same molecular formula but different structural formulas. Unit 2 • Investigation II

  27. Check-In • Are the following molecules correct according to HONC 1234? If not, what specifically is wrong with them? 1. 2. Unit 2 • Investigation II

  28. Wrap-Up • The HONC 1234 rule tells us how many times hydrogen, oxygen, nitrogen and carbon tend to bond. • When a molecule is oriented differently in space it is still the same molecule. • A molecular formula can be associated with more than one distinct structural formula. Unit 2 • Investigation II

  29. Smells Unit – Investigation II Lesson 3: Connect the Dots

  30. ChemCatalyst • This is a drawing of the structural formula of a methane molecule. The lines represent bonds. Explain what you think a bond is. Unit 2 • Investigation II

  31. The Big Question • How can Lewis dot symbols help us to understand and predict bonding? Unit 2 • Investigation II

  32. You will be able to: • Draw the Lewis dot symbol for an element and predict how many covalent bonds it will make. Unit 2 • Investigation II

  33. Notes • A covalent bond is a connection that forms between two atoms when those atoms are sharing a pair of electrons between them. (cont.) Unit 2 • Investigation II

  34. Notes(cont.) • When we draw an atom using dots to represent the valence electrons it is called a Lewis dot symbol. • When we draw a molecule using dots to represent the valence electrons it is called a Lewis dot structure. (cont.) Unit 2 • Investigation II

  35. Notes(cont.) • Nitrogen, with five valence electrons, would be drawn as follows: • Notice that the Lewis dot symbol of nitrogen has three unpaired electrons and one electron pair. This means that nitrogen has three electrons that can potentially be paired up with electrons from other atoms. (cont.) Unit 2 • Investigation II

  36. Notes(cont.) Unit 2 • Investigation II

  37. Activity • Purpose: In this lesson you will begin to understand why atoms connect to each other the way they do. You will be introduced to a tool, called Lewis dot symbols, which will assist you in building molecules and predicting how many bonds an element will have. (cont.) Unit 2 • Investigation II

  38. (cont.) • C N O F Ne • Si P S Cl Ar (cont.) Unit 2 • Investigation II

  39. (cont.) (cont.) Unit 2 • Investigation II

  40. (cont.) Unit 2 • Investigation II

  41. Making Sense • Based on what you’ve learned in this lesson, explain why the HONC 1234 rule works. Unit 2 • Investigation II

  42. Notes (cont.) Unit 2 • Investigation II

  43. Notes(cont.) • Bonded pair refers to a pair of electrons that are involved in bonding between two different atoms. • Lone pair refers to a pair of electrons that are not involved in bonding but are paired up within an atom. • A single electron is sometimes referred to as an unpaired electron. lone pair of electrons bonded pair of electrons Unit 2 • Investigation II

  44. Check-In • Draw the Lewis dot symbol for the element I, iodine. Explain how you arrived at your particular drawing. • How many covalent bonds does iodine make? Unit 2 • Investigation II

  45. Wrap-Up • A covalent bond is one in which two atoms share valence electrons. • In a Lewis dot structure, pairs of electrons that are not bonded are referred to as lone pairs. • HONC 1234 indicates how many unpaired electrons are associated with hydrogen, oxygen, nitrogen and carbon. Unit 2 • Investigation II

  46. Smells Unit – Investigation II Lesson 4: Eight is Enough

  47. ChemCatalyst • Draw the Lewis dot structure for the following covalently bonded molecule. Explain how you arrived at your answer. Cl2 Unit 2 • Investigation II

  48. The Big Question • How can we use Lewis dot structures to help draw structural formulas? Unit 2 • Investigation II

  49. You will be able to: • Predict whether a given compound would be stable and likely to be found in nature. Unit 2 • Investigation II

  50. Notes Unit 2 • Investigation II