Questions tagged [ideal-gas]

A gas that behaves as randomly moving, non-interacting molecules. This allows a simplified equation of state.

Filter by
Sorted by
Tagged with
0
votes
1answer
77 views

Gibbs theorem and partial molar volume

In the above, it's mentioned that any quantity other than MOLAR VOLUME can be written that way. But how can we say generalize it with certainty when molar volume itself doesn't fit in or to say any ...
4
votes
2answers
10k views

Calculate mass of air in a tyre from pressure

How can one calculate the mass of air inside a tyre, given a particular tyre size; a pressure, in $kPa = \frac{1000kg}{m\cdot s^2}$; and assuming room temperature, and normal air composition? I can't ...
0
votes
2answers
46 views

Deriving simple equation for volume and pressure, adiabatic exponent

I have $$VT^\frac{f}{2}=\text{constant}\tag1$$ and $$V^{\gamma}P=\text{constant}.\tag2$$ Where $V=\text{volume}, \ P=\text{pressure} , \ T=\text{temperature},$ $f=\text{number ...
0
votes
1answer
38 views

Potential energy of an ideal gas

According to equipartition theorem, for ideal gas in thermal equilibrium, each vibrational mode will get $kT/2$ for kinetic energy and $kT/2$ for potential energy. But at the same time, we assume ...
0
votes
0answers
49 views

A Baloon in a oil silo [closed]

I would like to submit you this problem. It was given last year at the admission exam of Rome's doctoral school of physics. I have some doubts about the second point. How would you solve it? A ...
0
votes
1answer
27 views

Converting Gas volume to Liquid Volume

For a test setup, I need to set CO2 flowrate as 130 L/h but I do not have a flow measuring device to set it. So I made one device as mentioned below. Once I set the flowrate, I will remove containers/...
2
votes
1answer
761 views

Flow rate of gas down a pipe at low pressures

I'm trying to understand an 'approximate derivation' of the flow rate of gas down a pipe at low pressure from my book (an example problem). It uses the result that the flux of a gas is given by $\...
1
vote
1answer
48 views

Particle in kinetic gas theory without collision

Hello I have a (Gedankenexperiment) question about the kinetic gas theory. As far as I understand temperature corresponds to kinetic energy. Assume now there would be one particle that does not ...
7
votes
3answers
642 views

Why Does A Ramjet Produce Net Forward Thrust

So every (non-technical) explanation of ramjets I've seen talks about how the intake slows and pressurizes the incoming air before combustion but then takes for granted the fact that burning fuel ...
1
vote
3answers
129 views

Constant RPM of Gas Compressor

I would like to improve my understanding of gas compressors. If the compressor is moving at constant RPM, does it mean that it can only allow the same volumetric flow rate at all times? So the power ...
0
votes
0answers
21 views

Internal energy of ideal gas in terms of sound speed and pressure

In thermodynamics two state variables can be treated as independent and any other variable can be determined from these two variables. We can assume sound speed and pressure as independent variables ...
3
votes
3answers
101 views

Thermodynamics : Pressure of a gas

While reading The kinetic Theory of gases in Feynman Lectures , i was hoping for an explanation concerning the factor (2) that shows that only half of the atoms are headed towards a piston, while the ...
0
votes
2answers
9k views

Why is $PV^\gamma$ constant in an adiabatic process?

In non isolated systems where there is no adiabatic process, $PV$ is constant. But the graph gets steeper in adiabatic process because of the $\gamma$ over the $V$. Why is it there in adiabatic ...
1
vote
1answer
329 views

Sudden volume increase piston

I am wondering what happens in the following situation. I have a piston filled with an ideal gas for which I suddenly/instantaneaouly iscrease the volume. In particular I want to know what happens to ...
1
vote
0answers
21 views

Is there a word for the availability of a gas, normalized for pressure?

As a bit of background of what I'm getting at, consider that for the purposes of humans breathing and getting oxygen into their blood, 20% oxygen at 1 atm is equivalent to 100% oxygen at .2 atm. ...
0
votes
1answer
45 views

Is internal energy frame-dependent? [duplicate]

In the realm of kinetic theory of gases, the internal energy of gas is solely due to the sum of kinetic energies of all particles, since kinetic energy is frame dependent I was thinking whether a ...
0
votes
1answer
41 views

(SOLVED) Calculate the velocity of a gas inputted in pressure difference

I'm trying to make a generally simple calculation but I'm not sure if I'm approaching this correctly. So as I'm making assumptions solving this problem, please comment or correct me wherever I'm wrong ...
0
votes
2answers
59 views

On internal energy conservation in a gas system

I have seen multiple questions which talk about a tank with a partition in the middle and different ideal gases on either side at some different value of pressure,volume and temperature and then they ...
-1
votes
1answer
41 views

What happens when ideal gasses are mixed?

I'm sure their temperatures will be equal, but what about their volumes and pressures?How does one approach ideal gas mixing problems?
0
votes
4answers
76 views

What happens to the pressure and the temperature of a gas compressed adiabatically?

The set-up is basic. There is a piston that goes down, reducing the volume. The process is adiabatic, so the acquired energy is kept inside the gas. The ideal gas law states that as the volume ...
3
votes
1answer
60 views

What does $C_p-C_v=R$ mean? What are its applications?

So my question is: what does $C_p-C_v=R$ actually mean? It's very straightforward to derive. But my issue is, where and what use does this have in real life applications, and why is it important? All ...
1
vote
0answers
46 views

Is it possible to calculate pressure without a barometer?

For an experiment, I need to pump air into a rocket with varying volumes of water, and thus air. However, I want to keep the pressure the same. Given the amount of air a bicycle pump can pump, the ...
1
vote
3answers
111 views

Expansion of an ideal gas in an evacuated bottle having nonconducting walls

In the free expansion of ideal gas in a vacuum $dW = 0$ as $p_{ext} = 0$ and $dU = 0$ therefore there is no change in temperature of the ideal gas also. what i want to know that can the following ...
-1
votes
2answers
193 views

What volume exactly does the $V$ term in ideal gas equation represent?

According to kinetic theory of gases 'the actual volume occupied by the gas molecules are negligible in comparison to the volume of the container.' I believe that this assumption is significant ...
1
vote
1answer
53 views

Pressure in a 2D Ideal Gas simulation

I am currently creating a 2D ideal gas simulator whereby the user can determine three of the four variables (P, V, n, T) and the gas would adjust accordingly. I was wondering how I could calculate ...
1
vote
1answer
168 views

Power of thermal radiation in gases

How much thermal radiation does a given volume of gas emit? Does it go according to Stefan-Boltzmann law, i.e. as $P=A\varepsilon \sigma T^4$, with $A$ as the cross-sectional area, $\varepsilon$ as ...
-1
votes
2answers
133 views

How do I simulate an ideal gas?

I wish to write a simple simulation of an ideal gas, but my maths and how I should have a model based the equation isn't quite up to it. I need some help understanding the relationship between ...
0
votes
2answers
230 views

Using the work-energy theorem in thermodynamics

If an $n$ moles of an ideal gas (one atomic) is heated at constant volume $V$ from temperature $T_1$ to temperature $T_2$, the amount of energy heat needed can be calculated as $$ Q = nC_V \Delta T $$...
1
vote
3answers
410 views

Ideal gas and moveable pistons

Suppose there is an ideal, monatomic gas contained in a cylinder with a moveable piston and you bring that system (system = gas only) through some process. If that process changes the volume (or ...
1
vote
0answers
41 views

Finding the temperature of a gas using the $P$-$V$ diagram [closed]

I need to know a way to relate the P-V curve of an ideal gas to its temperature.I found a similar question on stackexchange but couldn't understand how the relationship between a point and the ...
0
votes
0answers
50 views

Reason for gas constant value

I know that it's derived from experimentation and it's natural but is there a specific reason that the value is $8.31\space J\space mol^{-1}\space K^{-1}\space$?
0
votes
1answer
34 views

Find the density of air at the given temperature and pressure [closed]

Find the density of air at $99$ kPa and $322.15$ K. My attempt: Let's assume that air is $78\%$ nitrogen and $22\%$ oxygen by volume. Average molar mass of air = $0.78\times 28+0.22\times 32\approx ...
1
vote
2answers
130 views

Internal energy

Internal energy at a specific state can't be calculated, but using kinetic theory of gases and the law of equipartition of energy, average kinetic energy is directly proportional to temperature. For ...
0
votes
3answers
3k views

Ideal gas formula $PV = nRT$ in Celsius scale

I was wondering how to re-write that ideal gas formula $PV = nRT$ applicable to Celsius or Fahrenheit scale. I know $R$ has unit $\frac{\mathrm J}{\mathrm{mol\cdot K}}$ and $T$ has units in K, that ...
1
vote
0answers
38 views

How do I calculate the pressure on the walls of my MD simulation?

So I've built a simulation in vpython where I have multiple hard balls that collide with each other and with the walls of the cube I've placed them in. I then replaced the values for their radius and ...
2
votes
0answers
40 views

Confused about summing over the velocity squared term

Consider a cubical box, L on each side. The box contains N molecules of ideal gas, each of mass m. All collisions are elastic. The force exerted by one molecule when it collides with a wall of ...
1
vote
1answer
136 views

What is the difference between the Method of Characteristics being formulated in terms of theta & alpha and theta & nu?

So I'm doing an MSc thesis involving the method of characteristics in rocket nozzles. My lecture notes have the MoC formulated such that the positive characteristics are defined as: C+ = Tan ( $\...
0
votes
0answers
22 views

Why maxwells speed distribution law doesn’t violet special theory if relativity [duplicate]

As per maxwells distribution law the molecule of gas will have speed across zero to infinity with some probability function. I want to know that why the speed above speed of light is possible (i know ...
0
votes
1answer
196 views

Calculating entropy for the surroundings the logical way doesn't work

EDIT: I was missing the entropy change due to temperature change and now everything makes sense Suppose I have $n$ mol of an ideal gas in a chamber with a piston with volume $V$ at pressure $P_{1}$ ...
3
votes
2answers
84 views

Ideal gas law when diatomic molecule is about to break into constituents

Suppose we have a diatomic molecule. Its center of mass has an average kinetic energy given by $$ \frac{1}{2} (m_1 +m_2) v_{cm}^2 = \frac{3}{2}k_BT $$ and using this we can derive the ideal gas law ...
0
votes
1answer
122 views

Derive Charles's Law from ideal gas equation

For a thermodynamics experiment I had to determine the ratio of the volumes of two tanks. The process used was isothermal. I pressurized up one tank and slowly opened the valve between the two tanks ...
0
votes
1answer
156 views

Mixture of different gases filling their container

If I have a closed container with a mixture of two or more gases $\rho_1$ and $\rho_2$ for instance at thermal equilibrium where $\rho_1>\rho_2$ how would I determine what percentage of the ...
0
votes
2answers
169 views

How to Convert Dimension of $R$ constant of Air (J/Kg.K)?

Example) (P=nRT/V) in this equation P=nRT/V, The final dimension is achieved should be a function of pressure, But I can not understand this dimension in final (mol.J/Kg.Liter). when use in R ...
0
votes
1answer
173 views

Helium in an old mylar balloon

As a sealed mylar foil balloon ages, it deflates. I assume that this is mostly due to the monoatomic helium escaping through the envelope material. (In much the same manner as hydrogen can escape ...
1
vote
2answers
87 views

What is the volume occupied?

What is the volume occupied by 1 mole of gas at $10^{−10}$ torr, the pressure inside an “ultra high vacuum” (UHV) chamber. How do I solve this problem without being given the temperature?
0
votes
2answers
194 views

Two gases seperated by semi-permeable membrane

The problem is as follows: Two ideal gases are contained adiabatically and separated by an insulating, fixed piston that blocks the molecules of gas 2 but allows the molecules of gas 1 through(in both ...
3
votes
2answers
667 views

In a gravitational field, will the temperature of an ideal gas will be lower at higher altitude?

I know there are similar questions, but I have some arguments which seem to explain that temperature of an ideal gas in a gravitational field will be lower at higher altitudes. I am assuming that: 1....
0
votes
0answers
16 views

Why is the probability that the collision angle will be in the range of 0 to 60 degrees than in the range of 60 to 180 degrees

Pretty much the title. It is given that the probability that the collision angle will be in the range of 0 to 60 degrees than in the range of 60 to 180 degrees I don't remember seeing such statement ...
1
vote
3answers
163 views

Is it possible to increase the temperature of an ideal gas in an adiabatic sealed container with a frictionless piston for a lid?

As far as I understand it, if I pumped the piston repeatedly, compressing the gas, the temperature would go up for a second, but the minute I released the piston the higher pressure inside the ...
0
votes
1answer
49 views

Work done by ideal gas under a reversible process which is not isobaric, isochoric, isothermal, adiabatic

First post, sorry for the poor formatting. Question Consider a non adiabatic system closed to mass exchange where an ideal gas traverses along a reversible path from state: to . What is the work ...