Is Total Molar Concentration Constant in an Isothermal System?

In summary, the total molar concentration in an isobaric isothermal system remains constant due to the ability of napthalene atoms to enter the gas phase and maintain equilibrium. This is in contrast to the perfect gas equation where volume can change and affect the number of moles. However, it must always be constant and equal to 1, regardless of the specific conditions such as constant temperature and pressure. This raises the question of whether the equation C=CA+CB is always true or only for constant temperature and pressure.
  • #1
mech-eng
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how can we understand total molar concentration remains constant in a isobaric isothermal system? if it is from perfect gas equation pv=nrt although p and t are constant but v isn't constant so since mol number can be change over volume, total molar concentration may change.it is a situation of a tube with one end is surrounded by gaseous nitrogen and one end is closed with a solid naphthalene in equilibrium with its vapor.
 
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  • #2
Total molar concentration remains constant because n can change
probably: if it is solid napthalene in equilibrium with its vapor, then napthalene atoms can desorb and enter the gas phase to maintain equilibrium. so if volume changes, n will change correspondingly
 
  • #3
But it must always be constant which is equal to 1 so we shouldn't limit the situation to the isobaric isothermal case.Am I right? is C=CA+CB always true or only for at constant
T and P
 
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1. What is an isobaric isothermal system?

An isobaric isothermal system is a thermodynamic system where the pressure and temperature are kept constant. This means that any changes in the system will not affect its pressure or temperature.

2. How does an isobaric isothermal system differ from other thermodynamic systems?

An isobaric isothermal system differs from other thermodynamic systems, such as isochoric and adiabatic systems, because it maintains a constant pressure and temperature throughout any changes in the system.

3. What are some real-world examples of isobaric isothermal systems?

Some examples of isobaric isothermal systems include a boiling pot of water on a stove, a refrigerator, and a car engine running at a constant speed on a flat road.

4. What are the main principles that govern an isobaric isothermal system?

The main principles that govern an isobaric isothermal system are the ideal gas law, which states that pressure and temperature are directly proportional, and the first law of thermodynamics, which states that energy cannot be created or destroyed, only transferred.

5. How can an isobaric isothermal system be used in scientific research?

An isobaric isothermal system can be used in various scientific research, such as studying the behavior of gases, chemical reactions, and the properties of materials at different temperatures and pressures. It can also be used in engineering applications, such as in the design of engines and refrigeration systems.

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