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A student wrote:

If I expand an ideal gas from V1 to V2 under constant external pressure and pex, then the work done

is w = -p_{ex}(V2 - V1). As a result, if the expansion
is isothermal, then as delta U = q + w = 0, then

q = -w = p_{ex}(V2 - V1). Therefore, delta S
=q_{rev}/T=(p/T)(V2 - V1).

Is this statement correct or incorrect? Explain your answer.

Answer #1

A Joule expansion refers to the expansion of a gas from volume
V1 to volume V2 against no
applied pressure, and is sometimes also called a free expansion.
There is no work done, because the P of -PdV is
zero. By insulating the system, this process can be done
adiabatically, so there is no change in heat. For an ideal gas, the
adiabatic process is also isothermal, so there is no change in
thermodynamic energy, ∆U = 0 (which is...

Suppose 4.00 mol of an ideal gas undergoes a reversible
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Thermodynamics Question
A Joule expansion refers to the expansion of a gas from volume
V1 to volume V2against no
applied pressure, and is sometimes also called a free expansion.
There is no work done, because the P of -PdV is
zero. By insulating the system, this process can be done
adiabatically, so there is no change in heat. For an ideal gas, the
adiabatic process is also isothermal, so there is no change in
thermodynamic energy, ∆U = 0 (which...

Physics_2_2.5
An ideal monatomic gas is in a vessel with the volume V1 = 1m3
under the pressure p1 = 2 105 Pa. The gas is first heated at a
constant pressure to the Volume V2 = 3m3 and then at constant
volume to the pressure p2 = 5 105 Pa. Find the amount of heat Q
supplied to the gas.
A clear process is highly appreciated! Thank you so much for the
help!

Consider an ideal gas enclosed in a 1.00 L container at an
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Calculate the work, w, if the gas expands against a constant
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w=____J
Now calculate the work done if this process is carried out in
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1. First, let the gas expand against a constant external
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2. From there, let the...

21.3 moles of a diatomic ideal gas undergo three steps:
A to B is an isobaric (constant pressure P1
= 4.15x106 Pascal) expansion from volume
V1 = 0.0609 m3 to
V2 = 0.934 m3.
B to C is isochoric (constant volume)
C to A is isothermal (constant T).
During the isobaric expansion from A to B: find Q, the heat
transferred, in Joules. Give your answer in scientific
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NOTE: A positive sign means heat has
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See diagram 4.
58 moles of a diatomic ideal gas undergo three steps:
A to B is an isobaric (constant pressure P1 = 5.71x10^6 Pascal)
expansion from volume V1 = 0.025 m3 to V2 = 0.661 m3.
B to C is isochoric (constant volume)
C to A is isothermal (constant T).
Find PC, the pressure at point C, in Pascals. Express in
scientific notation.

Show that the work done by an ideal gas during an isothermal
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A piston-cylinder device contains 0.2 kg of air, initially at
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Determine: (a) The work done during this process, and
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In the initial state, an ideal gas has pressure p1, volume V1
and temperature T1. Now the gas changes its state by effecting a
state change so that it reaches the pressure p2, the volume V2 and
the temperature T2 in the new state. The pressure doubles during
this state change, which is an isochore process.
a) Find the work W performed during the isochore process.
b) The heat Q is exchanged between the gas and the surroundings
during the...

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