All Questions
Tagged with degrees-of-freedom ideal-gas
19 questions
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Vibrational degree of freedom for monoatomic gases
I read that, when the temperature of a gas becomes high enough, a third type of degree of freedom becomes accessible, viz. the vibrational degree of freedom.
Also (at high temperatures) there is a ...
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3
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Doubt regarding kinetic theory of gases
My school teacher had told me that one of the assumptions of Kinetic Theory of Gases was that the molecules of a given gas were all identical and to be considered as very small elastic spheres. ...
- 123
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5
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Why expansion of real gases lead to cooling?
Paul Hewitt writes in his book
Expansion of real gases lead to cooling as average translational kinetic energy per molecule decreases.
The reason given is:
During Expansion molecules collide with ...
- 1,395
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Number of degrees of freedom for a gaseous mixture
I came across the formula to find the number of degrees of freedom in a gaseous mixture which is as follows:
$$f_\mathrm{mix}
=\frac{\sum n_if_i}{\sum n_i}$$
Now it has been mentioned in this lecture ...
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2
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Why don't we use the "degree of freedom" as a factor in the ideal gas equation?
For an adiabatic process, the ideal gas follows the equation
$$ PV^{\gamma}= constant$$
The equation above implies that the pressure of an ideal gas (under adiabatic process) depends on the "...
- 8,476
5
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2
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344
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All possible choices for two independent thermodynamic variables for a one-component, one-phase system
I am confused about the independent variables in thermodynamics. I know that for a one-component, one-phase system, there are only two independent intensive variables that can be chosen and which ...
- 474
-1
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2
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How many Degrees of Freedom do Linear Triatomic Gas Molecules Have and Why?
I read this in one of my textbooks that stated
Linear Triatomic Gas Molecules like CO2, HCN, CS2 in which all the atoms are linear, the total number of degrees of freedom are
Nf = NT + NR + NV
where ...
0
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2
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287
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Why do some gases have fewer degrees of freedom at same temperature?
I am trying to understand the degres of freedom for gases.
Air has 5 degrees of freedom at room temperature but why does Argon, $Ar$ have 3 degrees of freedom while $O_2$ has 5 at the same temperature ...
- 285
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Does the ideal gas law apply to gases which consist of more than one atom?
In the derivation of the ideal gas law, one sets for the average kinetical energy $f = 3$ degrees of freedom. This refers to the transition in x,y,z axes. This is true for gases, which consist of only ...
- 361
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Kelvin and kinetic theory of gases
I know that the degree of freedom increase by 2 when the temperature is high and decrease by 2 when the temperature is low. A dumb question here, what temperature is considered as 'high temperature' ...
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Why does $H_2$ have $C_V$=$7/2 R$ at high temperatures, while the total number of degrees of freedom is 6?
The two hydrogen atoms have 6 degrees of freedom in total. Of them, $3$ contribute to translation, $2 $contribute to rotation and $1$ contribute to the vibration.
I know that the vibrations motion is ...
- 3,270
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Number of degrees of fredom in diatomic molecule model
In the book of Salinas the author says in chapter The Ideal Quantum Gas he says and I quote
The classical models of a gas of diatomic molecules (a rigid rotator in three dimensions, or a rotator ...
user78217
2
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1
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87
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Kinetic theory of physics [closed]
$$E = (3/2) kT$$
For average kinetic energy of a molecule gas.The constant $k$ does not depend on the type of molecule. Can this result be true for both hydrogen and chlorine?
- 21
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7/2 versus 9/2 for diatomic heat capacity
Question
I calculated the classical heat capacity of a diatomic gas as $C_V = (9/2)Nk_B$, however the accepted value is $C_V = (7/2)Nk_B$.
I assumed the classical Hamiltonian of two identical atoms ...
- 2,107
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2
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13k
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Why energy at room temperature $= kT$ and not $(3/2)kT$ [duplicate]
I always see that a room temperature of $T=300\,\text{K}$ corresponds to an energy of $k_BT \approx \frac{1}{40}\,\text{eV}$. But shouldn't it be $\frac{3}{2}k_BT$ since the molecules in the air have ...
- 163
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Amount of unknown parameters in compressible Euler equations
I'm looking at this page for the compressible Euler equations.
To me it seems, in the 1-dimensional case, there should be 3 unknowns: density, velocity, and pressure. This is because the energy $E$ ...
- 103
2
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1
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3k
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Why is molar specific heat at constant volume of a monatomic ideal gas a constant?
I thought specific heat varies depending on the substance. Why is it always $(3/2) R$?
- 143
4
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3
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$E=kT$ or $\frac32kT$?
Basically, which is the correct formula for thermal energy, and is this the same as kinetic energy? My notes are pretty conflicting on this topic, and I'm getting pretty confused.
- 51
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7
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How to deduce $E=(3/2)kT$?
It says in my course notes for undergraduate environmental physics that a particle has so-called "kinetic energy"
$$E=\frac{3}{2}kT=\frac{1}{2}mv^{2}$$
Where does this formula come from? What is $k$?...
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