smells unit – investigation ii

Smells Unit – Investigation II

Lesson 2:Honk If You Like Molecules

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Admit Slip

• Examine the following molecules. What patterns do you see in the bonding of hydrogen, oxygen, carbon, and nitrogen?

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Agenda

• Admit Slip• Notes• Classwork• Homework

Product: Notes and HomeworkHomework: Last page of packet

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

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.

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

• HONC 1234 is a phrase that helps us remember the bonding of hydrogen, oxygen, nitrogen and carbon.

• 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)

Structural Formulas 12 / 6 /10

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

• Molecules are isomers of one another

if they have the same molecular formula but different structural formulas.

Notes (cont.)

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

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.)

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Time for Classwork!

If you finish early, work on the homework!

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Answer Review

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Molecular formula #1 (the same molecule drawn with two different orientations)

H

H

C CC

HH

HH

H

H

H

H

C

C

C

H

H

H

H

H

H

(cont.)

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Molecular formula #2 (four different drawings are shown – three different molecules are represented)

H

H

C CC

HH

HH

H

H

OH

H

C CC

H

H

HH

H

HO

O

H

H

C CC

HH

H

H

H

H

H

CC

HH

H

H

H

O C

H

H

(cont.)

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Molecular formula #3 (four different drawings are shown – however, they represent only three different structures)

H

C CC

HH

HH

H

H

N

H

H

H

C CC

HH

HH

H

H

N

H

H

H

C CC

H

H

HH

H

H

N

H

H

H

C CC

HH

H

H

H

N H

H

H

(cont.)

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Making Sense

• The third molecular formula has at least three possible structures. Are these all the same molecule? Explain.

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

Exit Slip

• Are the following molecules correct according to HONC 1234? If not, what specifically is wrong with them?

1. 2.H

C

H

H O H C

H

H

H

C

H

O

H

H

C

H

H

© 2004 Key Curriculum Press.

Unit 2 • Investigation II

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.