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Two moles of oxygen gas, which can be regarded as an Ideal gas with Cv = 22,1 JK 'mol, are maintained at 273k in a volume of 0,1 m ³ under 1 Sothermal conditions. Then, the gas is compressed reversibly to half of its original volume at constant pressure calculate P₁ and P2 Cp W, Show all derivation steps qp​

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5 votes

Answer:

P1 = 45,174 Pa

P2 = 90,348 Pa

W = 2,259 J

Q = 2,259 J

ΔS = 0

Step-by-step explanation:

We can use the ideal gas law, PV = nRT, to solve this problem. Since the gas is at constant temperature (isothermal), we can simplify this to PV = constant.

Given that there are two moles of oxygen gas in a volume of 0.1 m^3 at 273 K, we can calculate the initial pressure as follows:

P1V1 = nRT

P1 = nRT/V1

P1 = (2 mol)(8.31 J/mol.K)(273 K)/(0.1 m^3)

P1 = 45,174 Pa

Next, we compress the gas reversibly to half of its original volume (i.e. V2 = 0.05 m^3) at constant pressure. We can use the same equation, PV = constant, and the fact that the pressure is constant to solve for the final pressure:

P1V1 = P2V2

P2 = P1V1/V2

P2 = (45,174 Pa)(0.1 m^3)/(0.05 m^3)

P2 = 90,348 Pa

Now, we can calculate the work done during the compression process using the equation:

W = -PΔV

where ΔV is the change in volume (i.e. V2 - V1 = -0.05 m^3), and the negative sign indicates that work is done on the system during compression. Substituting the values, we get:

W = -(45,174 Pa)(-0.05 m^3)

W = 2,259 J

Finally, we can calculate the heat added to the system using the first law of thermodynamics:

ΔU = Q - W

where ΔU is the change in internal energy (which is zero since the temperature is constant), Q is the heat added to the system, and W is the work done on the system (which is negative). Solving for Q, we get:

Q = ΔU + W

Q = 0 J + 2,259 J

Q = 2,259 J

Since the temperature is constant, the heat added to the system is equal to the change in enthalpy:

ΔH = Q = 2,259 J

We can also calculate the change in entropy using the equation:

ΔS = nCv ln(T2/T1)

where Cv is the molar heat capacity at constant volume (which is given as 22.1 J/K.mol), and ln(T2/T1) is the natural logarithm of the ratio of final and initial temperatures. Since the temperature is constant, ΔS = 0.

Therefore, the final answers are:

P1 = 45,174 Pa

P2 = 90,348 Pa

W = 2,259 J

Q = 2,259 J

ΔS = 0

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User Ggonmar
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