Lecture Notes on Condensed Structural Formulas

Introduction

• Presenter: Brent Kadrowski
• Topic: Understanding and drawing condensed structural formulas
• Prerequisite: Basic understanding of Lewis structures

Overview of Condensed Structural Formulas

• Definition: Abbreviated versions of Lewis structures
  • Characteristics: Leave out bonds and lone pairs
  • Purpose: Convey the same connectivity information but in a more compact, easier-to-draw format
  • Usefulness: Particularly helpful in word processing programs

Example 1: Butane Structure

• Lewis Structure: Includes all bonds
• Condensed Structural Formula Process:
  • Group bonded atoms together
  • Examples:
    • CH3 for carbon bonded to three hydrogens
    • CH2 for carbon bonded to two hydrogens
• Connectivity: Retained without showing bonds
• Repeating Groups: Can use parentheses and subscript
  • Example: (CH2)2

Example 2: Ethanol Structure

• Steps:
  • CH3 for C bonded to three H's
  • CH2 for C bonded to two H's
  • OH for the hydroxyl group (lone pairs not shown)

Writing Condensed Structural Formulas

• Multiple Representations:
  • Recognize equivalent ways to represent groups
  • Example: CH3(CH)3 vs HCC(CH3)3

Converting Condensed Formulas to Lewis Structures

• Strategy:
  • Read from left to right
  • Identify central atoms and attached groups
  • Example: Start with central C for (CH3CH2)3C

Handling Double Bonds

• Alkenes (C=C):
  • Often shown with double lines between carbons
  • Example: CH3CH=CHCH3
• Aesthetic Variations: Swapping positions for clarity

Carbon-Oxygen Double Bonds

• Ketones: C=O
  • Often represented as CO in condensed formulas
  • Example: CH2COCH3
• Variations: Parentheses for clarity

Examples of Oxygen-Containing Functional Groups

• Carboxylic Acids: COOH or CO2H
  • Example: CH3COOH
• Aldehydes: CHO
  • Important to distinguish from COH (alcohol)
  • Example: CH3CHO

Conclusion

• Further Learning: Check skeletal structures and other video series
• Call to Action: Subscribe to Brent Kadrowski's channel for more content