In nature, there are many atoms in bound form, forming a special association called molecules.However, inert gases, justifying its name, form monohydric unit.The molecular structure of a substance usually involves covalent bonds.But there are also so-called conditionally weak interactions between atoms.Molecules can be enormous, consisting of millions of atoms.Where is there is such a complex molecular structure?Examples - a plurality of organic compounds such as the quaternary structure of proteins and DNA.
covalent bonds that hold atoms together, is extremely strong.However, the physical properties of the substance do not depend on this, they depend on the van der Waals forces and hydrogen bonds, which provide interaction between adjacent structures of the fragments to each other.The molecular structure of liquid, gas or solid substances legkoplavyaschihsya explains the physical state in which we observe them at a certain temperature.To change the state of matter, just heat it or cool.Covalent bonds are not broken in this case.
boundaries begin the process
How high or low points will be gasification and melting?It depends on the strength of intermolecular interactions.Hydrogen bonds in a material increase in temperature changes the state of aggregation.The larger the molecule, the more their Van der Waals interactions, the more difficult to make a solid liquid or liquid gas.
Most of the known compounds are not soluble in water at all.And those who still dissolve, interact, often with the formation of new hydrogen bonds.Example - ammonia.He is able to break the hydrogen bonds between water molecules and successfully build their own.In parallel, the ion exchange reaction, but it does not play a big role in the dissolution of ammonia.Basically this process ammonia is obliged to hydrogen bonds.The response is the same in both directions, the process can, under certain temperature and pressure at all to be in balance.Other solutes, such as ethanol and sugar also bind c excellent water by means of intermolecular interactions.
solubility in organic liquids is provided by the formation of Van der Waals bonds.Proper interaction with the solvent are destroyed.The soluble substance is bound to its molecules to form a homogeneous mixture in appearance.Too many processes of life made possible by these properties of organic substances.
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Why are most of the substances does not conduct electricity?The molecular structure does not allow!For the current need simultaneous movement of a large number of electrons, a kind of "farm" of them.This is what happens in metals, non-metals but have almost never happens.At the boundary in respect of the properties are semiconductor materials having electric conductivity depending on the environment.
Many physical processes are easy to explain if there is information about the molecular structure of the substance.Aggregate states are well understood by modern physics.