The concept of specific heat it is used in the field of physical with reference to hot which requires one substance per unit mass to achieve increase its temperature by one degree Celsius .
To understand the notion, therefore, we must have several clear ideas. Is called hot , in the context of physics, to the energy that moves from one body to another, causing changes in state and a dilation. The dough On the other hand, it is a physical quantity that refers to the amount of matter that is present in a body. The temperature Finally, it is another physical magnitude, in this case oriented to the level of heat that the environment or a body has.
If we take these concepts and link them to the definition mentioned in the first paragraph, we can see that the specific heat is the Energy You need a unit of mass of a substance to increase its heat by a degree Celsius.
The specific heat, which can be represented with a letter C lowercase (c ), is usually linked to the initial temperature of the substance It is an intensive property of the matter : It is not related to your quantity or size.
As the specific heat of a substance grows, a greater amount of heat is needed to achieve increased temperature . If we take the case of substances in a gaseous state, we may notice that the nitrogen It has a specific mass heat higher than oxygen . Therefore, more energy is needed to achieve the increase of heat in a unit of mass of nitrogen than of oxygen.
The origin of the name of this concept is found in the investigations of the Scottish physicist Joseph Black, who carried out various calorimetric experiments and coined the phrase "capacity for heat ". Calorimetry, meanwhile, is the branch of physics that aims to measure heat in a change of state or a chemical reaction using an instrument known as calorimeter.
It is important to keep in mind that Joseph Black was born in the year 1728 and that he died a year before the beginning of the 19th century, so the vision that science had of these and others phenomena It was very different from today. For example, thermodynamics and mechanics were taken as independent sciences, and this leads us to think that the term "specific heat", conceived at the time, is not entirely consistent with the current ideas of science; however, since it has taken root in the community, they continue to use it without modifying it.
With respect to the equations that we must use to calculate the specific heat value, we can say that the average specific heat capacity (which is represented by the symbol & ccirc; ) corresponds to a interval of temperatures defined as follows: & ccirc; = Q / mΔT .
The variable Q represents the energy that is transferred between two systems or between one and its surroundings, in the form of heat. m , on the other hand, corresponds to the mass of system (If we were treating the specific molar heat, then we should use the letter n). Finally there is the temperature delta (ΔT ), that is, the temperature rise that the system is going through. We must not forget that the two variables found after the division sign must be multiplied with each other (m by ΔT ).
In engineering, the measurement of the specific heat usually has the amount of substance the mass, both in kilograms like in grams. In chemistry, on the other hand, it is convenient to use the unity mol.