Homogeneous mixtures of two substances with each other that do not react are called solutions . It is necessary, in each case, that there be a substance of majority proportion and another (or others) of smaller proportions, which are dissolved in the majority. The concentrations of each combination can be specified in different ways, the simplest being the distribution of percentages of solute and solvent.
On the other hand, also the molarity and the parts per million are options for the realization of the analysis of the concentration. As for the states of aggregation, all the combinations between these states can present mixtures that combine, appearing in some cases more frequently than others.
The mixtures between a gas and a solid also obey the dissolution category, and can be done in both directions: the greater proportion being that of the solid, or the gas proportion. The case in which a solid is diffused in a gas is not too common but it usually happens that solid substances such as naphthalene are combined in the air that is a gas , entering the process of sublimation generating a solution. In effect, the combinations of gas and solid that have the solid as a solute are restricted to powder-type solids that diffuse into gases.
In the other direction, it is more common for a gas to diffuse into a solid , especially in the case of hydrogen as gas, which is capable of being stored by some metals and used as the case may be. This is a very particular characteristic of the mixture between solids and gases, since much research is done to optimize storage.
Compared to the other hydrocarbons, hydrogen is usually much more difficult to store and transport given the resources and current technology: this is because the tanks in which they can be stored should be much larger, and in their liquid form it must be stored in cryogenic form at an extremely cold temperature, and tanks with thermal insulation are also very expensive.
There are some metals that are especially suitable for hydrogen storage, where palladium can be highlighted: at room temperature and atmospheric pressure, palladium can absorb up to 900 times its own volume of hydrogen, in a process that is reversible and can be manipulated Thus, the challenge of the industry is to give the best possible use to this property characteristic of some metals.
Exposed the ways in which the combination between a gas and a solid can be presented , the following list includes examples of this combination.
- Any kind of smoke (diffusion of solids inside a gas)
- Volcanic dust
- Smog particles present in the air
- Hydrogen dissolved in platinum
- Naphthalene sublimated in the air
- Solid spray
- Hydrogen in palladium
- Solid sulfur
- Environmental dust in the air
- Pollen scattered in the wind