3.6.2
Trends in Physical Properties
Trends in Physical Properties
Trends in Physical Properties
Physical properties in organic compounds, such as boiling point and solubility, depend on the intermolecular forces that occur between molecules.
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Intermolecular forces
Intermolecular forces
- Physical properties in organic compounds, depend on the intermolecular forces that occur between molecules.
- Intermolecular forces vary when:
- changing the molar mass (number of electrons)
- changing the amount of branching
- changing the functional group


Boiling point (volatility)
Boiling point (volatility)
- As the chain becomes longer in a homologous series the boiling point increases, as shown above.


Boiling point (volatility) cont.
Boiling point (volatility) cont.
- The increase in boiling point is attributed to stronger London dispersion forces between molecules.
- Compounds with high boiling points have low volatilities and ones with low boiling points have high volatilities.
- Branched structural isomers typically have lower boiling points as more branching results in a more spherical conformation and lower surface contact.


Boiling point (volatility) cont.
Boiling point (volatility) cont.
- The functional group present in the molecule also influences the boiling point.
- The main types of functional groups and their corresponding intermolecular forces are summarised in the table above.


Solubility
Solubility
- Hydrocarbons are soluble in apolar (aliphatic) solvents and are insoluble in water.
- Ethanol is soluble in water as it can hydrogen bond with water.
- Increasing the carbon-chain length makes the alcohol become less soluble in water.
- Hexan-1-ol has limited solubility in water and decan-1-ol is practically insoluble in water.
1Structure - Models of the Particulate of Matter
1.1Introduction to the Particulate Model of Matter
1.2The Nuclear Atom
1.3Electron Configuration
1.4Counting Particles by Mass: The Mole
1.6Elements, Compounds & Mixtures
1.7States of Matter & Changes of State
1.8Reacting Masses &. Volumes
1.9Solutions
2Structure - Models of Bonding & Structure
2.1The Ionic Model
2.2The Covalent Model
2.3Covalent Structures
2.4The Metallic Model
2.5From Models to Materials
2.6Valence Electrons & Ionic Compounds
2.7Molecular Shape
3Structure - Classification of Matter
3.1The Periodic Table: Classification of Elements
3.2Periodic Trends
3.3Group 1 Alkali Metals
3.4Halogens
3.5Noble gases, group 18
3.6Functional Groups: Classification of Organic
3.7Functional Group Chemistry
3.8Alkanes
3.9Alcohols
4Reactivity - What Drives Chemical Reaction?
4.1Endothermic & Exothermic Reactions
4.2Enthalpy of Reaction, Formation, & Hess' Law
5Reactivity - How Much, How Fast & How Far?
5.1Kinetics
5.2Rates of Reaction
5.3Stoichometry
5.4Le Châtelier’s Principle
5.5Introduction to Equilibrium
5.6Equilibrium Constant
5.7Reaction Quotient & Equilibrium Constant
6Reactivity - The Mechanisms of Chemical Change
6.1Proton Transfer Reactions
6.2The pH Scale
6.3Strong & Weak Acids and Bases
6.4Acid Deposition
6.5Types of Organic Reactions
6.6Oxidation & Reduction
6.7Electrochemical Cells
6.9Acid-Base Titrations
6.9.1Titration Calculation Weak Acid & Strong Base
6.9.2Titration Experimental Detail
6.9.3Extended Response - Titration
6.9.4Titration Calculations
6.9.5Titration Curves
6.9.6Titration Calculation Strong Acid & Weak Base
6.9.7IB Multiple Choice - Titrations
6.9.8Polyprotic Acids
6.9.9Titration Calculations Strong Acid & Strong Base
6.9.10Titrations Curves 2
7Measurement, Data Processing & Analysis
7.1Uncertainties & Errors in Measurements & Results
7.2Graphical Techniques
7.3Spectroscopic Identification of Organic Compounds
7.4Infrared Spectroscpy
Jump to other topics
1Structure - Models of the Particulate of Matter
1.1Introduction to the Particulate Model of Matter
1.2The Nuclear Atom
1.3Electron Configuration
1.4Counting Particles by Mass: The Mole
1.6Elements, Compounds & Mixtures
1.7States of Matter & Changes of State
1.8Reacting Masses &. Volumes
1.9Solutions
2Structure - Models of Bonding & Structure
2.1The Ionic Model
2.2The Covalent Model
2.3Covalent Structures
2.4The Metallic Model
2.5From Models to Materials
2.6Valence Electrons & Ionic Compounds
2.7Molecular Shape
3Structure - Classification of Matter
3.1The Periodic Table: Classification of Elements
3.2Periodic Trends
3.3Group 1 Alkali Metals
3.4Halogens
3.5Noble gases, group 18
3.6Functional Groups: Classification of Organic
3.7Functional Group Chemistry
3.8Alkanes
3.9Alcohols
4Reactivity - What Drives Chemical Reaction?
4.1Endothermic & Exothermic Reactions
4.2Enthalpy of Reaction, Formation, & Hess' Law
5Reactivity - How Much, How Fast & How Far?
5.1Kinetics
5.2Rates of Reaction
5.3Stoichometry
5.4Le Châtelier’s Principle
5.5Introduction to Equilibrium
5.6Equilibrium Constant
5.7Reaction Quotient & Equilibrium Constant
6Reactivity - The Mechanisms of Chemical Change
6.1Proton Transfer Reactions
6.2The pH Scale
6.3Strong & Weak Acids and Bases
6.4Acid Deposition
6.5Types of Organic Reactions
6.6Oxidation & Reduction
6.7Electrochemical Cells
6.9Acid-Base Titrations
6.9.1Titration Calculation Weak Acid & Strong Base
6.9.2Titration Experimental Detail
6.9.3Extended Response - Titration
6.9.4Titration Calculations
6.9.5Titration Curves
6.9.6Titration Calculation Strong Acid & Weak Base
6.9.7IB Multiple Choice - Titrations
6.9.8Polyprotic Acids
6.9.9Titration Calculations Strong Acid & Strong Base
6.9.10Titrations Curves 2
7Measurement, Data Processing & Analysis
7.1Uncertainties & Errors in Measurements & Results
7.2Graphical Techniques
7.3Spectroscopic Identification of Organic Compounds
7.4Infrared Spectroscpy
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