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Given: mass=6kg , initial volume=0.3m^3, temp=215C, final volume=0.15m^3, isothermally compressed in closed piston cylinder Find: Initial Pressure, Final Pressure

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To answer this question, we will make use of some fundamental principles in thermodynamics. Here are the givens:

- Universal gas constant (R) = 8.314 J/(mol*K)
- Molar mass of air (M) = 0.02897 kg/mol
- Mass of air (mass) = 6 kg
- Initial volume of air (initial_volume) = 0.3 m^3
- Final volume of air (final_volume) = 0.15 m^3
- Temperature of air (temp) = 215C which is equivalent to 215 + 273.15 = 488.15 K in Kelvin scale.

The first step is to find the number of moles of air (n) using the equation:

n = mass / M = 6 kg / 0.02897 kg/mol = 207.105 moles

Now, we use the Ideal Gas Law equation P=nRT/V to figure out the initial and final pressure of the air. The Ideal Gas Law states that the pressure of a certain amount of gas is directly proportional to its temperature and volume and inversely proportional to its volume.

The pressure is calculated by the equation: P = nRT/V

First, let's calculate the initial pressure. We know the number of moles (n), universal gas constant (R), temperature (T) in Kelvin, and initial volume (V):

P_initial = nRT / initial_volume = 207.105 moles * 8.314 J/(mol*K) * 488.15 K / 0.3 m^3 = 2801849.568519158 Pa

Then we calculate the final pressure when the volume of air has reduced to final_volume:

P_final = nRT / final_volume = 207.105 moles * 8.314 J/(mol*K) * 488.15 K / 0.15 m^3 = 5603699.137038316 Pa

So, the initial pressure of the air is 2801849.568519158 Pascal (Pa)
and the final pressure of the air when it's isothermally compressed to a volume of 0.15 m^3 is 5603699.137038316 Pascal (Pa).

It's expected that the pressure would increase after the compression because the volume of the gas decreases while the temperature remains constant throughout the process.

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