Chemical Engineering Thermodynamics

Q1:

Specific heat of a gas for a reversible adiabatic process is

A negative

B zero

C infinity

D none of these

ANS:B - zero

For a reversible adiabatic process, the specific heat of a gas is none of these. Specific heat (𝐶C) is defined as the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. It can be expressed as: 𝐶=𝛿𝑄𝑚⋅𝑑𝑇C=m⋅dTδQ​ Where:

  • 𝐶C is the specific heat.
  • 𝛿𝑄δQ is the heat added to or removed from the system.
  • 𝑚m is the mass of the substance.
  • 𝑑𝑇dT is the change in temperature.
In a reversible adiabatic process, there is no heat exchange (𝛿𝑄=0δQ=0) between the system and its surroundings. Therefore, the specific heat cannot be determined directly from this definition because there is no heat added or removed. Instead, for an ideal gas undergoing a reversible adiabatic process, the specific heat at constant pressure (𝐶𝑝Cp​) and the specific heat at constant volume (𝐶𝑉CV​) are related by the following equation: 𝐶𝑝−𝐶𝑉=𝑅Cp​−CV​=R Where 𝑅R is the gas constant. So, in the case of a reversible adiabatic process, while the specific heats 𝐶𝑝Cp​ and 𝐶𝑉CV​ are not directly applicable, their difference (𝐶𝑝−𝐶𝑉Cp​−CV​) is a constant, which is the gas constant 𝑅R.



img not found
img

For help Students Orientation
Mcqs Questions

One stop destination for examination, preparation, recruitment, and more. Specially designed online test to solve all your preparation worries. Go wherever you want to and practice whenever you want, using the online test platform.