Through the three gas transformations (isothermal, isobaric, isovolumetric) represented respectively by the equations: PV = K, V/T = K, P/T = K, the General Gas Equation was reached:
Note that the equation addresses the three state variables (P, V, and T). Therefore, it is possible to know the volume, temperature and pressure of a gas if we base ourselves on this equation.
Let's look at an example:
The diagram above represents the transformations of a fixed mass of gas, based on it we can answer the following questions:
- What is the gas pressure value at the point THE? Note that point A is located at the value 2.0 in vector P (atm), so we say that the atmospheric pressure value at A is 2 atm.
- And the pressure value at the point B? Note that this point is at the same position as A with respect to vector P (atm). Therefore, B obeys the same conditions as A and has the same pressure: 2 atm.
- What gaseous transformation occurs in the passage from A to B?
Isobaric transformation, as the gas pressure is constant (2 atm) and the volume varies, from 4 liters (point A) to 8 liters (point B).
- And the volume at the point Ç? If we subtract B – A, we get the volume of C = 4 liters.
- Considering C and A: the pressure at these points varies, but the volume does not. We then have an Isovolumetric gas transformation.
By Líria Alves
Graduated in Chemistry
Brazil School Team
See more!
gas transformations
General chemistry - Chemistry - Brazil School
Source: Brazil School - https://brasilescola.uol.com.br/quimica/equacao-geral-dos-gases.htm
