Question

Как зависят силы межмолекулярного действия от расстояния между молекулами

Answer 1

Межмолекулярные взаимодействия, взаимодействия молекул между собой, не приводящее к разрыву или образованию новых химических связей. Межмолекулярные взаимодействия определяют отличие реальных газов от идеальных, существование жидкостей и молекулярных кристаллов. От межмолекулярных взаимодействий зависят многие структурные, спектральные, термодинамические, теплофизические и другие свойства веществ. Появление понятия межмолекулярные взаимодействия связано с именем Й. Д. Ван-дер-Ваальса, который для объяснения свойств реальных газов и жидкостей предложил в 1873 уравнение состояния, учитывающее межмолекулярные взаимодействия. Поэтому силы межмолекулярного взаимодействия часто называют ван-дер-ваальсовыми.

Answer 2

The Relationship Between Intermolecular Forces and Distance

The strength of intermolecular forces is influenced by the distance between molecules. Intermolecular forces are the attractive or repulsive forces that exist between molecules. These forces play a crucial role in determining the physical properties of substances, such as boiling point, melting point, and solubility.

As the distance between molecules decreases, the strength of intermolecular forces generally increases. This is because the attractive forces between molecules become stronger when they are closer together. Conversely, as the distance between molecules increases, the strength of intermolecular forces decreases.

There are several types of intermolecular forces, including:

1. London dispersion forces: These forces are present in all molecules and arise from temporary fluctuations in electron distribution. They are the weakest intermolecular forces and increase with increasing molecular size and surface area.

2. Dipole-dipole forces: These forces occur between polar molecules that have a permanent dipole moment. The strength of dipole-dipole forces depends on the magnitude of the dipole moment and the distance between the molecules.

3. Hydrogen bonding: Hydrogen bonding is a special type of dipole-dipole interaction that occurs when a hydrogen atom is bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and is attracted to another electronegative atom in a nearby molecule. Hydrogen bonding is stronger than regular dipole-dipole forces.

4. Ion-dipole forces: These forces occur between an ion and a polar molecule. They are particularly important in solutions where ions are dissolved in a polar solvent.

It is important to note that the strength of intermolecular forces is not solely determined by distance. Other factors, such as molecular shape, polarity, and the presence of functional groups, also play a role in determining the strength of intermolecular forces.

Overall, the relationship between intermolecular forces and distance is that as the distance between molecules decreases, the strength of intermolecular forces generally increases. However, the specific type and strength of intermolecular forces can vary depending on the nature of the molecules involved.