Molecular structure and physical properties

In nature, many atoms exist in a bound form, forming special associations called molecules. However, inert gases, justifying their name, form monatomic units. The molecular structure of a substance usually implies covalent bonds. But there are also so-called conditionally weak interactions between atoms. Molecules can be huge, consisting of millions of atoms. Where is such a complex molecular structure? Examples are a variety of organic substances, such as proteins with a quaternary structure and DNA.

Without chemistry

The covalent bonds that hold the atoms together are extremely strong. But the physical properties of matter do not depend on this, they depend on van der Waals forces and hydrogen bonds, which ensure the interaction of neighboring fragments of structures with each other. The molecular structure of a liquid, a gas, or a low-melting solid substance also explains the aggregate state in which we observe them at a certain temperature. In order to change the state of the substance, it is enough just to heat it or cool it. Covalent bonds do not break.

Process start boundaries

How high or low are the points of gas formation and melting? It depends on the strength of intermolecular interactions. Hydrogen bonds in matter increase the temperature of the change in the aggregate state. The larger the molecule, the more van der Waals interactions in them, the harder it is to make a liquid or liquid gaseous.

Features of ammonia

Most of the known substances in water are not soluble at all. And those that are still dissolved, come into contact, often with the formation of new hydrogen bonds. An example is ammonia. It is able to destroy hydrogen bonds between water molecules and successfully build their own. In parallel, the ion exchange reaction takes place, but it does not play a big role in the dissolution of ammonia. Basically, this process ammonia is due to hydrogen bonds. The reaction goes both ways, the process can be at equilibrium at a certain temperature and pressure. Other soluble substances, for example ethanol and sugars, also perfectly bind to water by intermolecular interactions.

Other reasons

Solubility in organic liquids is provided by the formation of van der Waals connections. The own interactions of the solvent are destroyed. The soluble substance binds to its molecules, forming a homogeneous mixture. Very many vital processes became possible due to these properties of organic substances.

Toku - no

Why do most substances not conduct electricity? Molecular structure does not allow! For the current, it is necessary to simultaneously move a large number of electrons, a kind of "collective farm" of them. This is the case with metals, but non-metals almost never exist. At the border with respect to this property are semiconductor materials that have a conductivity dependent on the medium.

Many physical processes are easily explained, if there is information about the molecular structure of the substance. Aggregate states are well studied by modern physics.