Specific heat capacity for adiabatic & isothermal process

In summary: The heat capacity is a property that defines how much energy is saved in a material for a given change of temperature. That is a correct definition, provided that the temperature change is virtual. Otherwise the two definitions would be identical.
  • #1
metalrose
113
0
Can we define specific heat capacity for an adiabatic process ??

Would it always be zero since dQ is 0 for an adiabatic process?

Also, can we define specific heat capacity for isothermal processes ?
Would it be infinity in all cases?

Just want to verify if I am thinking along the correct lines.
 
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  • #2
The heat capacity is a property that defines how much energy is saved in a material for a given change of temperature. A definition of it will -- out of necessity -- always contain a (possibly virtual) change of temperature. In the equation of state one other variable will have to be allowed to change to keep the equation of state satisfied. You could also keep some other value constant like p+a*V.Your way of defining heat capacity doesn't look right. In an adiabatic process the gas changes temperature because the energy invested in work will go into the gas and has no time to escape. From dQ = 0 for the whole process doesn't follow anything about the gas' heat capacity.
 
  • #3
0xDEADBEEF said:
The heat capacity is a property that defines how much energy is saved in a material for a given change of temperature.
If that was the definition, Cp and Cv would be the same. The energy saved in a gas that undergoes a certain temperature change is the same whether the temperature change occurs during expansion at constant pressure or at constant volume. But we know from the first law that this cannot be the case.

A definition of it will -- out of necessity -- always contain a (possibly virtual) change of temperature. In the equation of state one other variable will have to be allowed to change to keep the equation of state satisfied. You could also keep some other value constant like p+a*V.Your way of defining heat capacity doesn't look right. In an adiabatic process the gas changes temperature because the energy invested in work will go into the gas and has no time to escape. From dQ = 0 for the whole process doesn't follow anything about the gas' heat capacity.
The heat capacity at 0 heat flow is a rather meaningless term. It is like asking the mileage a car gets when it is standing still. If the OP wants to define what he means by heat capacity when there is 0 heat flow, perhaps we could give some meaning to the concept.
 
1)

What is the difference between adiabatic and isothermal processes?

In an adiabatic process, there is no exchange of heat between the system and its surroundings, while in an isothermal process, the temperature of the system remains constant. This means that in an adiabatic process, the change in internal energy is equal to the work done on or by the system, while in an isothermal process, the change in internal energy is equal to zero.

2)

How does the specific heat capacity affect adiabatic and isothermal processes?

The specific heat capacity is a measure of how much heat energy is required to raise the temperature of a substance by a certain amount. In an adiabatic process, the specific heat capacity is not a factor since no heat is exchanged. In an isothermal process, the specific heat capacity determines how much heat must be added or removed to maintain a constant temperature.

3)

What is the formula for calculating specific heat capacity?

The formula for specific heat capacity is Q = mcΔT, where Q is the heat energy added or removed, m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature.

4)

How does the specific heat capacity of a substance affect its thermal conductivity?

The specific heat capacity of a substance is directly related to its thermal conductivity. A substance with a higher specific heat capacity will require more heat energy to change its temperature, making it a poor conductor of heat. Conversely, a substance with a lower specific heat capacity will require less heat energy to change its temperature, making it a good conductor of heat.

5)

Can adiabatic and isothermal processes occur in real-life situations?

Yes, both adiabatic and isothermal processes can occur in real-life situations. For example, a thermos is designed to keep hot liquids hot and cold liquids cold by using an adiabatic process. On the other hand, a refrigerator uses an isothermal process to maintain a constant temperature inside.

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