What is Isobaric process: Definition and 30 Discussions
In thermodynamics, an isobaric process is a type of thermodynamic process in which the pressure of the system stays constant: ΔP = 0. The heat transferred to the system does work, but also changes the internal energy (U) of the system. This article uses the physics sign convention for work, where positive work is work done by the system. Using this convention, by the first law of thermodynamics,
Q
=
Δ
U
+
W
{\displaystyle Q=\Delta U+W\,}
where W is work, U is internal energy, and Q is heat. Pressure-volume work by the closed system is defined as:
W
=
∫
p
d
V
{\displaystyle W=\int \!p\,dV\,}
where Δ means change over the whole process, whereas d denotes a differential. Since pressure is constant, this means that
W
=
p
Δ
V
{\displaystyle W=p\Delta V\,}
.Applying the ideal gas law, this becomes
W
=
n
R
Δ
T
{\displaystyle W=n\,R\,\Delta T}
with R representing the gas constant, and n representing the amount of substance, which is assumed to remain constant (e.g., there is no phase transition during a chemical reaction). According to the equipartition theorem, the change in internal energy is related to the temperature of the system by
Δ
U
=
n
c
V
,
m
Δ
T
{\displaystyle \Delta U=n\,c_{V,m}\,\Delta T}
,where cV, m is molar heat capacity at a constant volume.
Substituting the last two equations into the first equation produces:
Q
=
n
c
V
,
m
Δ
T
+
n
R
Δ
T
Q
=
n
Δ
T
(
c
V
,
m
+
R
)
Q
=
n
Δ
T
c
P
,
m
{\displaystyle {\begin{aligned}Q&=n\,c_{V,m}\,\Delta T+n\,R\,\Delta T\\Q&=n\Delta T(c_{V,m}+R)\\Q&=n\Delta Tc_{P,m}\end{aligned}}}
where cP is molar heat capacity at a constant pressure.
Homework Statement: A PV diagram shows an isobaric expansion, I'm asked to know the signs of: work done on, heat added to, and change in energy content of the system.
Homework Equations: W= integral (P dV), dU = Q + W
Since this is an expansion, the system does work on the surrounding and...
Homework Statement
Consider a 1000 to 700 hPa layer in the atmosphere that is at rest and is in hydrostatic balance. The layer is subjected to radiative cooling at a rate of 5.0e3 J/s/m2 for one hour.
a) Calculate the change in mean temperature for the layer assuming all energy goes into...
Consider the following problem:
Gaseous helium (assumed ideal) filled in a horizontal cylindrical vessel is separated from its surroundings by a massless piston. Both piston and cylinder are thermally insulating. The ambient pressure is suddenly tripled without changing the ambient temperature...
What is wrong with this logic, if any? It does not seem like this should be true but maybe I'm mistaken.
Assuming the process consists of two isobaric processes and two isothermal processes the work from B to C in terms of p1, p2, V1, and V2 is given by the following.
1) WBC=p2(VC-VB)
2)...
Homework Statement
[/B]
This is a very basic question. I have a cylinder filled with air having stops at a particular height .
First part of the process is isobaric as piston is free to move and P is constant.
When piston reaches stops this becomes isochoric process as volume is constant.
So...
Homework Statement
A cylinder contains 0.250mol of carbon dioxide (CO2) gas at a temperature of 27.0∘C. The cylinder is provided with a frictionless piston, which maintains a constant pressure of 1.00atm on the gas. The gas is heated until its temperature increases to 127.0∘C. Assume that the...
Homework Statement
This is probably a real easy task for most, but I simply CANNOT manage to calculate it, even given the correct answer. I will translate it as best I can and hope I don't phrase it in a way that causes misunderstandings:
12 Moles of an ideal gas go through an Isobaric...
Homework Statement
A gas bottle contains exactly 158 moles of carbon dioxide CO2. Find the change in the internal energy of this much CO2 when it is cooled from 36C down to exactly 25C at a constant pressure of 1 atm. The gas can be treated as an ideal gas with γ=1.289. The gas constant reads...
1. Homework Statement
When volume changes from V to 2V at constant pressure then the change in internal enrgy will be?
2. Homework Equations
ΔU= nCvΔT
3. The Attempt at a Solution
I have used the equation ΔU= nCvΔT but the answer is PV/γ-1
Homework Statement
[/B]
You are asked to calculate changes in internal energy, entropy, heat transferred and work done for each of the following process. Also you are asked to calculate "the latent heat for the isotherm in the figure".
We know the a and b parameters which characterize the VdW...
We have an ideal gas enclosed in cylinder whose top is covered by a piston of certain weight ##mg##. At this stage, the piston is at rest which means the force by which the gas acts on the piston (##F=PA## where ## P## is the gas pressure and ##A## is the cross sectional area of the cylinder) is...
Homework Statement
How much work is done on the gas in the process shown in figure P12.24. This is from College Physics: A strategic approach, 2nd addition, by Knight, et al. Ch.12, #24
The graph shown is kPa vs V(cm^3). It's a constant temperature process (isobaric) at 200 kpa. I was able to...
In an isobaric process of 1 mole of a monatomic ideal gas, the pressure stays the same while the volume and temperature change. Let's take an isobaric expansion where the volume increases by 2m3 and the pressure stays at 5kPa.
If the work done by the gas is the pressure times the change in...
Homework Statement
Assume nitrogen gas (N2) is an ideal gas. n = 7.57 moles of N2 gas are heated isobarically (at constant pressure) from temperature To = 18.6 oC to temperature Tf = 50.9 oC. Find:
c) ΔIE, the change in internal energy of the N2 gas
Homework Equations
Change in IE...
Homework Statement
n = 1.46 moles of ideal gas are heated isobarically (at constant pressure) from temperature To = 431 oC to temperature Tf = 1227 oC. Find: change in Energy, Q, W.
Homework Equations
Change in IE = Q + W
W (isobaric process) = P(vf-v1)
The Attempt at a Solution...
Hey,
during last lecture of thermodynamics we did polytropic processes, and with no
discuss teacher said, that isobaric process is in general polytropic. If we had ideal
gas, then it is clear, bud what if the gas isn't ideal?
I tried to proof it, but I stuck and don't know how to continue...
Hi there,
I'm having a great deal of trouble with this thermodynamics question.
Cylinder filled with steam at 350 kN/m2. Initial volume is 0.05 m3. Sufficient heat transfer is effected to raise the internal energy in each cylinder by 50 kJ. The piston is moved slowly to maintain the...
Hi! I have this experiment, that keeps getting me frustrated. The experiment is simple:
We have hot water and a long plastic tube with one end closed. We simply measure how much water is in the tube and from that we get the water volume (water is in cylinder shape).
But there is something I...
Hello All, I am interpreting a diagram from the following question.
(I didnt have a chance to take thermo and I learned it by myself so I might have some problems)
http://www.physicsgrad.com/pgre/9677-15
I understand that I can just do ΔW and I get the right answer,
but upon doing it...
hi ...
These days i am trying to make sense of the various processes of thermodynamics and so far i have tried the isothermal process , and isochoric process (which is quite simple i think). Now i am trying to describe what i have understood by the isobaric process:
According to the basic...
I know this question has been done to death and I have had a look through past questions on this forum and others but I can't find anything that is helpful to this particular question!
Homework Statement
An ideal monatomic gas expands reversibly at a fixed pressure of 10^5 Pa from a...
Homework Statement
http://img140.imageshack.us/img140/2963/isobaricsteam.jpg
P1 and P2 are 1 bar. V2 4.812 and V2 specific volume is 2.406
X1=0.6
Homework Equations
v=vf+x(vf-vg)
W=-P(v2-v1)
Q=(u2+pv2)-(u1+pv1)
The Attempt at a Solution
Hi guys first timer here...
Homework Statement
One mole of an ideal monatomic gas is taken through the cycle ABCA shown schematically
in the diagram. State A has volume 0.0208 m3 and pressure 1.22 × 10 5 Pa, and state C has volume 0.0524 m3 Process CA lies along the 305 ±1 K isotherm. The molar heat capacities for...
Can anyone help me with understanding what is going on at page 11 of these notes?
http://www.chem.utoronto.ca/coursenotes/CHM223/Section%205B%20Fall%202010.pdf
Do you get why there is 2 delta Gs? I am really confused with what he
was trying to do there?
ΔG(37oC) – ΔG(25oC) ≈ – (T – 298)...
Homework Statement
Pf
429
Q
-754
ΔU
819
The table above shows the measurements taken while an ideal gas underwent an ISOBARIC process. Fill in the appropriate values for the table below.
ΔP=?
Homework Equations
Q= ΔU+W=ΔU=PΔV
The Attempt at a Solution
I don't know how to go...
NVM I solved it. Thanks for reading anyway :)
Homework Statement
610 J of heat is added to 3.4 mol of a monatomic ideal gas at constant pressure. Find the
change of temperature of the gas.Homework Equations
At isobaric conditions, w = p\DeltaV = nR\DeltaT
w = nR\DeltaTThe Attempt at a...
[SOLVED] Isobaric process
Hi, need some help with this.
I got to moles of an ideal gas that are heated at constant pressure from T=27 C to T=107C.
How do I calculate the work done by the gas?
I know that for a isobaric process the work is given by
W = p(V2-V1)
Thanks
Homework Statement
Consider 1 gram of an ideal gas undergoing isobaric process. Suppose del(H) be the amount of heat given to it. Then,
del(H) = dU + del(W)
del(H) = 1 x C(v)dT + (P.dV)/J...
This problem is going to make me go crazy...
4. In the figure below, an ideal gas is slowly compressed at a constant pressure of 2.0 atm from 10.0 L to 2.0 L. This process is represented as the path B to D. In this process, some heat flows out and the temperature drops. If the heat lost from...
Question:
When a quantity of monatomic ideal gas expands at a constant pressure of 4.00 \times 10^{4} {\rm Pa}, the volume of the gas increases from 2.00 \times 10^{ - 3} {\rm m}^{3} to 8.00 \times 10^{ - 3} {\rm m}^{3}.
A.
What is the change in the internal energy of the gas?
It's isobaric...