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One mole of an ideal gas is initially in a chamber of volume (1.0 times 10^{-2} m^3) and at a temperature of 27°C. (a) How much heat is absorbed by the gas when it slowly expands isothermally to twice its initial volume? (b) Suppose the gas is slowly transformed to the same final state by first decreasing the pressure at constant volume and then expanding it isobarically. What is the heat transferred for this case? (c) Calculate the heat transferred when the gas is transformed quasi-statically to the same final state by expanding it isobarically, then decreasing its pressure at constant volume.

a) Find the heat absorbed during isothermal expansion.
b) Determine the heat transferred in the described process.
c) Calculate the heat in the quasi-static transformation.

User OneFineDay
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Final answer:

In an isothermal expansion, the heat absorbed can be found using the ideal gas law. The heat transferred in the described process can be calculated by considering two separate steps. In the quasi-static transformation, the heat transferred is zero due to it being isothermal.

Step-by-step explanation:

In order to solve this problem, we need to use the ideal gas law and the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system: ΔU = Q - W

(a) To find the heat absorbed during the isothermal expansion, we can use the formula:

Q = nRT ln(Vf/Vi)

where Q is the heat absorbed, n is the number of moles of gas, R is the gas constant, T is the initial temperature, and Vf and Vi are the final and initial volumes respectively.

Plugging in the given values, we have:

Q = (1 mol)(8.31 J/mol·K)(300 K) ln(2) ≈ 1447 J

(b) To find the heat transferred in the described process, we need to consider two separate steps: first, the decrease in pressure at constant volume, which involves no heat transfer as it is adiabatic; and second, the isobaric expansion, for which we can use the formula:

Q = nCpΔT

where Q is the heat transferred, n is the number of moles of gas, Cp is the molar heat capacity at constant pressure, and ΔT is the temperature change.

Given that it is isothermal, the temperature change is zero, so the heat transferred for this case is also zero.

(c) To calculate the heat transfer when the gas is transformed quasi-statically, we use the same formula as in part (b) for the isobaric expansion, with the difference that there is also a decrease in pressure at constant volume before the expansion:

Q = nCpΔT

Again, since it is isothermal, the change in temperature is zero, so the heat transfer in this case is also zero.

User Chimerical
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