How does intermolecular forces affect freezing point

Dipole-Dipole Interactions — The second-strongest type of intermolecular force, dipole-dipole interactions forms in molecules that contain electronegative atoms such as oxygen, nitrogen, and any of the halides such as chlorine and fluorine.

For example, a hydrocarbon molecule containing fluorine will form dipole-dipole interactions. The electronegative fluorine atom will pull the electron density towards it, making it have a partial negative charge.

The connecting atom, carbon, loses some of that electron density and thus gains a partial negative charge. This forms a temporary dipole at the fluorine-carbon bond. As opposite charges attract, the partially negative fluorine is attracted to the partially positive carbon of another neighboring molecule, forming a dipole-dipole interaction.

London dispersion forces — This type of interaction is a form of van der Waals forces and is present in all compounds. London dispersion forces are the weakest type of intermolecular forces. Like dipole-dipole interactions, there is a redistribution of electron density around the molecule, causing the formation of temporary charges. Unlike dipole-dipole interactions, the dipoles formed in London dispersion forces are very weak and minimal.

For example, nonpolar compounds like methane, ethane, pentane, and octane interact via London dispersion forces. The surface area and length of the molecule determines the strength of the attractive forces, such that compounds with more surface area have greater London dispersion forces than smaller compounds. Therefore, octane would have stronger London dispersion forces than methane. The Effect of Impurities on Melting Points Reported literature values of melting points assume that you have a pure sample of the compound in question.

Please enter your institutional email to check if you have access to this content. Please create an account to get access. Forgot Password? Two liquids that do not mix to an appreciable extent are called immiscible.

For example, nonpolar hexane is immiscible in polar water. Relatively weak attractive forces between the hexane and water do not adequately overcome the stronger hydrogen bonding forces between water molecules.

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Your access has now expired. Provide feedback to your librarian. If you have any questions, please do not hesitate to reach out to our customer success team. Login processing Chapter Liquids, Solids, and Intermolecular Forces.

Chapter 1: Introduction: Matter and Measurement. Chapter 2: Atoms and Elements. Chapter 3: Molecules, Compounds, and Chemical Equations. Chapter 4: Chemical Quantities and Aqueous Reactions. Chapter 5: Gases. Chapter 6: Thermochemistry. Chapter 7: Electronic Structure of Atoms. Chapter 8: Periodic Properties of the Elements. Chapter 9: Chemical Bonding: Basic Concepts. Chapter Solutions and Colloids. Chapter Chemical Kinetics. Chapter Chemical Equilibrium.

Chapter Acids and Bases. Chapter Acid-base and Solubility Equilibria. Chapter Thermodynamics. Chapter Electrochemistry. Chapter Radioactivity and Nuclear Chemistry. Molecules with stronger intermolecular force have higher freezing points. If we raise the temperature enough to overcome these forces, the solid will melt. Related questions How do intermolecular forces affect solvation?

How do intermolecular forces affect viscosity? This particular resource used the following sources:. Skip to main content. Search for:. Freezing Point Depression. Learning Objective Discuss the effects of a solute on the freezing point of a solvent. Key Points The freezing point depression can be calculated using the pure solvent freezing point and the molality of the solution.