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Smells Unit – Investigation II
Lesson 2:Honk If You Like Molecules
© 2004 Key Curriculum Press.
Unit 2 • Investigation II
Admit SlipHere 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?
© 2004 Key Curriculum Press.
Unit 2 • Investigation II
Agenda
• Admit Slip• Notes• Classwork• Exit Slip• Homework
Product: Notes, Classwork, Exit SlipHomework: 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
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.
Structural Formulas / HONC 12 / 10 /12
© 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 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)
© 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/structures.
Notes (cont.)
© 2004 Key Curriculum Press.
Structural Formula Drawing Tips
• It is best to start with the C’s. They make up the “carbon backbone” that is 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
© 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
1. C- H- O-
2. C3H8
Classwork Review
© 2004 Key Curriculum Press.
2. This is the same molecule drawn with two
different orientations)
Unit 2 • Investigation II
H
H
C CC
HH
HH
H
H
H
H
C
C
C
H
H
H
H
H
H
© 2004 Key Curriculum Press.
3. C3H8O
Unit 2 • Investigation II
© 2004 Key Curriculum Press.
Unit 2 • Investigation II
3. Four different drawings are possible – three different molecules (isomers) 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.
4. C3H9N
Unit 2 • Investigation II
© 2004 Key Curriculum Press.
Unit 2 • Investigation II
4. Four different drawings are possible – three different molecules (isomers) are represented)
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.
5. C3H6O with one C=O double bond.
Unit 2 • Investigation II
© 2004 Key Curriculum Press.
6. C4H8O2 with one C=O double bond
Unit 2 • Investigation II
© 2004 Key Curriculum Press.
7. C4H6O2 with two C=O double bonds.
Unit 2 • Investigation II
© 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.