# If the temperature changes in the adiabatic process

## What is the isothermal process and the adiabatic process - definition

### Isothermal process

Aisothermal process is athermodynamic process where thetemperature of the systemremains constant (T = const). The heat transfer into or out of the system typically has to take place at such a slow speed that it can continuously adapt to the temperature of the storage tank through heat exchange. That remains in each of these statesthermal equilibrium receive.

For aideal gasand a polytropic process corresponds to the casen = 1 oneisotherms Process (constant temperature). In contrast to theadiabatic process , in whichn = κ anda system does not exchange heat with its surroundings (Q = 0;∆T ≠ 0, the internal energy does not change in an isothermal process (due to ∆T = 0)) and thereforeΔU = 0 (for ideal gases) and Q ≠ 0. An adiabatic process is not necessarily an isothermal process, nor is an isothermal process necessarily adiabatic.

In technology, phase changes such as evaporation or melting are isothermal processes if they occur as usual at constant pressure and temperature.

### Isothermal process and the first law

The classical form of the first law of thermodynamics is the following equation:

dU = dQ - dW

In this equation, dW is the samedW = pdV and is known as the frontier work.

Atisothermal processes and theideal gas becomes the whole of the systemsupplied Heat used for the following work:

Isothermal process (dU = 0):

dU = 0 = Q - W → W = Q(for ideal gas)

Theisothermal process can with theideal gas law expressedbecome as:

pV = constant

or

p1 V.1 = p2 V.2

On a PV diagram, the process occurs along a line (called an isotherm) that has the equationp = constant / V .