Different Molar Heat Capacities For Gases
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Different Molar Heat Capacities For Gases
I'm still extremely confused on how gases could have multiple molar heat capacities. If you were to change the pressure or volume of a gas, you technically don't have to change the amount of moles of gas within the container right?
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Re: Different Molar Heat Capacities For Gases
I think when the volume is not constant (like with a piston), you need to take into account work (to move the piston?). im not quite sure though.
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Re: Different Molar Heat Capacities For Gases
Cv denotes the heat capacity of a gas at a constant volume while Cp denotes the heat capacity of a gas at constant pressure. We have two values because, when heating takes place at constant pressure, some of the heat is used to do expansion work rather than raise the temperature of the system. For a more thorough explanation, read section 8.9 in the textbook.
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Re: Different Molar Heat Capacities For Gases
For measuring heat transfer, the equation q=(n)(Cp)(delta T) relates molar heat capacity at a constant pressure with moles. If one were to change, the other would change accordingly. The relation changes if it is at constant volume instead.
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Re: Different Molar Heat Capacities For Gases
I'm still confused on the reason why there are two separate molar heat capacities. I know that substances expand when heated which would change the heat capacity assuming we have constant pressure, but what happens if we have a constant volume? How would having a constant volume affect molar heat capacity for a gas?
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Re: Different Molar Heat Capacities For Gases
The molar heat capacity at constant volume would be lower than that at constant pressure because all the heat goes into increasing the internal energy.
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