Enthalpy refers to the amount of energy that comes out of a substance, always keeping in mind the concept of chemistry and more specifically thermochemistry, which studies the heat of substances before their reactions; So what is enthalpy, definition and concept.
The amount of energy as such that comes out of a substance cannot be measured, so to measure enthalpy, the reactions of the elements and substances must be taken into account, as well as the chemical changes to which they must be exposed.
For this reason, the value of the transformations that are carried out between the energy of the elements or substances, which is the enthalpy itself, and the reactions that occur, is determined, taking into account the difference between one and the other.
- Chemical substances.
- Subject.
- Enthalpy.
- Reaction.
- Heat.
- Transformation.
- System.
Enthalpy, then, deals specifically with the heat emanating from substances when it comes to being under the same pressure, in order to be linked to its surroundings or surrounding environment, for this reason this variable must be known.
In the two disciplines of science, physics and chemistry, enthalpy is represented with a capital letter h (H), in addition, the measure to know its value is the joules, which measures the heat, work and energy of any type of substances in nature.
This process can be done in two different ways:
- Endothermic: those that consume the energy of the environment that surrounds them.
- Exothermic: energy is expelled into the environment that surrounds them.
This is how enthalpy works
- Thermochemical system. Enthalpy refers to the heat that emanates from bodies according to the pressure that is exerted on them, this being constant and depending on whether energy is released or, on the contrary, it is received from the outside to the inside in any of the reactions of a thermochemical system.
- The term enthalpy. The term was used for the first time by a Dutch physicist in 1913 thanks to his discovery in the chemical reactions that occur in chemistry through superconductivity, but which in the end comes to speak of the amount of heat or energy that is received. or is released.
- Combustion enthalpy. Combustion enthalpy is called the amount of energy that is released in the chemical process, in a mole of substance, which is the measure with which the amount of different materials or elements used in chemical reactions is calculated.
- Formation enthalpy. This type of transformation is carried out when a compound is finally made or produced, through the energy released by the elements that have reacted from the beginning according to the amount of each of them in one mole of substance.
- Decomposition enthalpy. Contrary to the previous one, this type of energy transformation, instead of forming a substance, breaks down into smaller substances until reaching the simplest, through reactions where heat or energy is released or collected in the chemical reaction.
- Combustion enthalpy. When the process of pressure that is exerted on matter is transformed in such a way that it is possible to have, after the energy of each of the substances present is released, oxygen in the form of a gas becomes part of this entire process.
- Neutralization enthalpy. It is the energy or force released during a reaction at the union of an acid solution and a totally basic one, depending on the amount of hydronium or hydroxide ions, depending on the concentration of one and the other in the transformation reactions.
- chemical enthalpies. The release or collection of energy by the elements serve a chemical reaction, the release of heat being released very important for what is the concept of chemistry, having its equivalent in the physical part.
- phase enthalpy. It is the change that is made when a substance changes from one state of matter to another through the enthalpy of release or collection of energy depending on the chemical process that is carried out, for this reason it is a transformation that is divided into: Vaporization enthalpy; Solidification enthalpy; Fusion enthalpy. In each of the changes that matter undergoes, the amount of substances can also be measured in addition to the heat, pressure or release of energy that is released from the moment the entire decomposition process begins.
- Dissolution enthalpy. It is the one that results from the dissolution of a solute or solid part of matter in a solvent, or liquid that is in charge of dissolving the first, through the release or absorption of energy, occurring in two well-defined phases depending on how it is done. one or the other process: Reticular (Absorption); Hydration (Release), Magnitude.
- Enthalpy is a quantity and as such must be represented by a function, mathematical formula or problem that must be solved, leading to a numerical expression at the end, knowing of course the release of energy that takes place in the process of the chemical reaction.
- The term to which enthalpy corresponds comes to represent the change in temperature as well as the movement of each of the elements involved in the decomposition process, either from liquid to solid or vice versa, as long as it is a positive reaction.
- constant pressure. It is the condition that is needed so that the enthalpy or measurement of the heat that the bodies emanate in a chemical reaction can be given, which can be atmospheric in most cases, making it subject to the entire system.
- The process that can be carried out with this is not a numerical value itself, but rather the change or transformation that the element undergoes when receiving heat or cold, always maintaining a value at the beginning and therefore a very different one at the end of everything.
Tips
- Find and investigate an example of enthalpy that will help you better recognize the process.
- Remember that changes usually occur at the level of solid or liquid elements.