Smells Unit – Investigation II

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

2. Admit Slip • Here are two examples of structural formulas of molecules. • How many times does each hydrogen (H) bond? • How many times does each oxygen (O) bond? • How many times does each nitrogen (N) bond? • How many times does each carbon (C) bond? Unit 2 • Investigation II

3. Agenda • Admit Slip • Notes • Classwork • Exit Slip • Homework Product: Notes, Classwork, Exit Slip Homework: Last page of packet Unit 2 • Investigation II

4. Today’s Objectives Students will be able to: • Explain the HONC 1234 Rule • Draw a structural formula for a molecule. • Determine whether the structural formula of a given molecule is possible. Unit 2 • Investigation II

5. Structural Formulas / HONC 12 / 5 /13 • A structural formula is a 2-dimensional 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 covalent bond. In a covalent bond, 2 electrons are being shared. • In structural formulas, the covalent bonds are represented as lines. Unit 2 • Investigation II

6. HONC 1234is a phrase that helps us remember the bonding of hydrogen, oxygen, nitrogen and carbon in structural formulas. • Hydrogen (H) forms 1 bond. • Oxygen (O) forms 2 bonds. • Nitrogen (N) forms 3 bonds. • Carbon (C) forms 4 bonds. • Double bonds and triple bonds still follow the HONC 1234 rule. (They count as 2 or 3 bonds) Unit 2 • Investigation II

7. Notes(cont.) • Molecules areisomers of one another if they have the same molecular formula but different structural formulas/structures. Unit 2 • Investigation II

8. Structural Formula Drawing Tips • It is best to start with the C’s. They make up the “carbon backbone” that goes down the middle of most molecules. • Add in any double or triple bonds and the O’s and N’s. • Last, add in the H’s. Unit 2 • Investigation II

9. 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

10. Time for Classwork! • If you finish early, work on the homework! Unit 2 • Investigation II

11. Classwork Review • C- H- O- • 2.C3H8 Unit 2 • Investigation II

12. 2. • This is the same molecule drawn with two different orientations) Unit 2 • Investigation II

13. 3. C3H8O Unit 2 • Investigation II

14. 3. Four different drawings are possible – three different molecules (isomers) are represented) (cont.) Unit 2 • Investigation II

15. 4. C3H9N Unit 2 • Investigation II

16. 4. Four different drawings are possible – three different molecules (isomers) are represented) (cont.) Unit 2 • Investigation II

17. 5. C3H6O with one C=O double bond. Unit 2 • Investigation II

18. 6. C4H8O2 with one C=O double bond Unit 2 • Investigation II

19. 7. C4H6O2 with two C=O double bonds. Unit 2 • Investigation II

20. Exit Slip • Are the following molecules correct according to HONC 1234? If not, what specifically is wrong with them? 1. 2. Unit 2 • Investigation II

21. 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