Questions tagged [volume]
The volume tag has no usage guidance.
234
questions
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16 views
What is the volume of water in an inclined pipe
Diagram:
I have a tank of water T, which was filled with 2000l of water. At some point along the pipe connected to it, there is a leak, which is leaking at the rate of 400l/24 hours.
Valve d and j ...
0
votes
1answer
25 views
Molar volume and compressibility factor [closed]
I want to estimate the molar volume of water vapor and after that I want to calculate the steam compressibility factor $Z$
Point A:
$p_A=50$ bar and temperature $623.15$ K
Point B:
$p_B=20$ bar
...
0
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1answer
39 views
Work done to compress a liquid in container [closed]
Into a compressed container containing water with pressure p and volume V we want to pump additional water. What is the work done? Unlike in the ideal gas, the work cannot be simply found out using ...
2
votes
3answers
63 views
Why does PV work consider total pressure instead of net pressure?
In physics, we define work as: $$W = F_{net}×d$$
However, in physical chemistry, PV work is calculated as:
$$W = P×ΔV$$
Why is total pressure used instead of net pressure? For example, if a gas is ...
0
votes
1answer
16 views
Typical balloon volume-pressure law
I need to find the gas pressure required to make a balloon take a given volume, knowing the gas densities and atmospheric pressure. Is there a typical law/correlation that can be used to approximate ...
1
vote
2answers
65 views
How do you define volume for gases? [closed]
Straight forward question. If atoms forming a gas float far from each other, how can we assign a volume to it? if it is in a container, perhaps we'd say the atoms, or molecules, reach every corner and ...
0
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1answer
76 views
Black hole mass
It has been taught to us that since the black holes have finite mass, their gravitational force is also finite, which totally fits. The Black hole anyhow has a singularity at it's center which is ...
0
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1answer
33 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
2answers
87 views
How can I compute the missing volume by looking at the pressure changes?
Disclaimer: I'm not in any shape used to deal with physics and forgive me in advance if this question is either out of scope of wrongly formulated.
I have a very practical problem. I have a container ...
2
votes
1answer
63 views
Can I tell whether a cycle is reversible or not by the $p$-$V$ diagram?
A thermodynamic process is reversible if the system remains in the equilibrium state throughout. That's what we are told in the book. My doubt is, though, can we judge whether a process is reversible ...
1
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1answer
77 views
Question about using Liouville's theorem to calculate time evolution of ensemble average
With the Liouville's theorem
$$\frac{{d\rho }}{{dt}} = \frac{{\partial \rho }}{{\partial t}} + \sum\limits_{a = 1}^{3N} {(\frac{{\partial \rho }}{{\partial {p_a}}}\frac{{d{p_a}}}{{dt}} + \frac{{\...
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0answers
25 views
Calculating infinitesimally small volume of a sphere in velocity space
This link (at the end of the page) is deriving the formula to calculate an infinitesimally small volume $dV$ on the surface of a sphere with radius $v$ in velocity space. It states that $dV = ...
1
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3answers
153 views
Shape of isotherms in $P$-$V$ phase diagram
Please explain the shape of the isotherms in this P-V phase diagram. In particular, why are the isotherms flat in the liquid-vapor region?
(image from Lumen Learning | Physics | Phase Changes)
0
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3answers
67 views
$pV$ work and Specific volume [closed]
I am working on a $pV$ work exercise. I am given $P_1$, $P_2$, and $V_1$; we can solve for $V_2$. I am also given mass. I am told that the $pV$ relationship is $pv^{1.2}=const.$, where $v$ is ...
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3answers
75 views
Energy Density is expressed in Liters, Liters of What?
When looking at energy density of batteries it is often expressed as Wh/L. For instance, Wikipedia says Lithium Ion batteries have a density of 250–693 W·h/L. Liters is supposed to express the volume ...
1
vote
2answers
106 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?
-2
votes
1answer
106 views
Did the Chernobyl power station's water cistern really hold $7000\:\rm m^3$? [closed]
In he HBO TV miniseries Chernobyl, they talk about a cistern holding 7000 cubic meters of water. That is the content of Loch Ness, the deepest lake in the UK. Would the Chernobyl reactor really hold ...
1
vote
1answer
32 views
How can internal energy be expressed as a function of any two of $p, v, T$?
In the book of Irey, Theormodynamics, the author states that (while talking about single phase substances)
For a simple compressible media, we may choose our measurable
independent variables any ...
0
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0answers
45 views
Thermodynamics, Phase change diagrammes
What would be the phenomena and PV, TV diagrammes for a closed vessel partially filled with water and subjected to heat, How change in vapour pressure would effect its boiling?, How PV, TV diagrammes ...
0
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3answers
73 views
Sign of $(\partial T /\partial V )_E$
Consider a realistic gas. If it is insulated and then allowed to expand into a vacuum, how does its temperature change?
We have to consider the sign of $\left(\dfrac{\partial T}{\partial V }\right)...
0
votes
2answers
48 views
Does the total energy in a volume (gas) increase linearly with increases in pressure?
If a volume has a certain pressure, then double that pressure at another time, is the total energy stored doubled? I'm sure this has to do with thermodynamics and if I remember correctly there is a ...
0
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2answers
51 views
What is the volume of liquid propane consumed when measuring gas flow at a given pressure?
We have a building with a large propane cylinder that distributes propane to different sources within the building. When the cylinder is filled, the propane is compressed to a liquid, and our bill is ...
1
vote
2answers
51 views
Change in Volume of Objects on applying stress
I came across a statement that whenever any stretching or compressing is done on any object, its change in volume is always greater than $0$.
This means that density always decreases (mass remaining ...
4
votes
3answers
226 views
Why is there Net Work Done on a Pressure/Volume Cycle?
The area enclosed by the rectangle is said to be the Net Work Done. My question is why would there be any net workdone if it returns to its initial position (W).
Shouldn't it act like a force-...
1
vote
1answer
50 views
Relationship between volume and surface density
I was not sure if it fits better here, or in the math forum, but this is the problem I am trying to solve:
Say you have a full cylinder of radius $R$, height $L$, and its uniformly charged with ...
3
votes
2answers
232 views
What is the volume inside the event horizon of a black hole?
As I understand it, we measure things like distance (and volume) by the speed of light. A meter is the distance light travels in 1/299792458 seconds. In "normal space" this is (barely) straightforward,...
1
vote
1answer
50 views
Definitions of area and volume in $d$-dim spacetime
I am reading Erik Verlinde's paper "Emergent Gravity and the Dark Universe". Equations 2.12 and 2.13 give the area $A(r)$ and volume $V(r)$ respectively. Do $d$ dimensions comprise of both space and ...
11
votes
1answer
1k views
Why is the ratio of two extensive quantities always intensive?
Is this something that we observe that always happens or is there some fundamental reason for two extensive quantities to give an intensive when divided?
0
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0answers
30 views
How can I get the height that sits above the waterline of a partly-submerged object?
If I know the density of water (say 1024 kg/m^3) and the density of ice (say 900 kg/m^3), and the volume of an object (say 8 x 10^9 m^3), how can I figure out how much of it is sitting above or below ...
1
vote
2answers
68 views
What happens to pressure when a liquid turns into a gas in a confined chamber?
I'm doing an experiment requiring immense pressures. Since I do not have access to a pump that can create these pressures I settled on something different...
Instead of using a pump I want to utilize ...
0
votes
1answer
30 views
Determining Gas Constant $R$ from Boyles Law?
I have done an experiment (Boyles Law experiment using Boyles Law Apparatus) in order to determine the value of the gas constant $R$. I have also taken into account the dead space volume in my ...
2
votes
1answer
95 views
Is 1 liter always equal to 1 cubic decimeter, independently of temperature, pressure, etc?
I recently found this conversion table for the unit conversion $\rm mmol/m^3 \ \leftrightarrow\ \rm mmol/L$ (millimoles per cubic meter to millimoles per liter)
My physics is very rusty, but just to ...
0
votes
1answer
80 views
What process is it when the polytropic index $n$ is equal to $- \infty$?
From
$$Pv^n = \mathrm{constant}$$
When $n = - \infty$
What kind of process is it....
Eg... When $n= \infty$,
It is constant volume....
Therefore when $n =- \infty$...
What is constant?
0
votes
1answer
113 views
How to calculate the mass of gas needed to fill a cylinder to a certain pressure?
I m tasked with a tricky situation. I need to calculate the exact amount a tank can take in gas. But I dont know the volume of the tank. I just need to make sure that the tank reaches the right ...
0
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0answers
66 views
Volume expansion rate
In the paper Backreaction in late-time cosmology by Thomas Buchert and Syksy Rasanen, Annual Review of Nuclear and Particle Science 62 (2012) 57-79, in eq .2.2 the covariant divergence:
$$\nabla_\...
0
votes
2answers
105 views
Change of specific internal energy due to temperature and volume
The change of internal energy due to temperature and volume may be written as
$$ dU=C_V dT + \left( T\left(\frac{\partial S}{\partial V}\right)_T-P\right) dV$$
where $$\left(\frac{\partial S}{\partial ...
0
votes
1answer
39 views
Two containers that have the same volume (let say 500 liter) but are different in shape
I remember from school, one time a teacher explain us the following:
two containers of the same volume, but one is thin and tall, and the second is short and wide.
then if we fill them with water from ...
0
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1answer
53 views
Is specific volume a function of temperature only (in liquids)?
As far as I know, you can take the equation $pv=RT$ (with
$v$ being the specific volume) for ideal gases. But I had a question in a quiz asking about this, and the answer was "dependent on ...
0
votes
1answer
72 views
An issue with thermodynamic properties of infinite systems
I have the following problem.
Given a finite system, let us say a box of side $L$ containing $N$ "ideal gas" non-interacting particles, properties such as the entropy can be defined, in this case, $S ...
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0answers
34 views
Is there an influence of the air humidity on the air expansion by a temperature change?
I have found the following formula to calculate the expansion of air by a temperature change, if the pressure stays at the same level:
ΔV = ɣ * V0 * ΔT
This would give me an expansion of 46.96m3 in ...
0
votes
2answers
40 views
$p$-$V$ diagram and internal energy
I recently learned that if the initial state is equal to the final state in the $p$-$V$ diagram then the internal energy is equal to zero so that means $Q=W$. My question is how can you know that only ...
1
vote
3answers
227 views
What's the difference in a PV diagram that is curved versus one that is straight?
So what would the difference be between the graph above versus one that has the same inital and final points but the path is curved. I'm sure it has something to do with temperature, so does it mean ...
2
votes
2answers
61 views
What is the point of generalizing a more specific result to an order of magnitude?
In my textbook, an example wants me to find an estimate of the number of cells in a human brain.
It gives the volume of the brain as $8 \times 10^{-3}\ \rm m^3$ which it then estimates further as $...
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0answers
38 views
Volume within equi-energetic surface of a classical harmonic oscillator in microcanonical ensemble
$$
V(E) = \int_{H\leq E} d\mu = \int_\Gamma d\mu\, \Theta\bigl(E-H(q,p)\bigr) .
$$
To compute the volume within the equinergetic surface in the microcanonical ensamble, we use the formula above, ...
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votes
4answers
644 views
Is it possible to find the volume of a 4 dimensional object? [closed]
I know there is 4 dimensional objects due to communicating with my friend group. I never found how would you find the volume because it was off the science channel.
0
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0answers
28 views
Determining pressure as a function of time for water filled balloon
Looking to determine pressure as a function of time for a water filled "balloon" at extremely high pressures (~90MPa) with a fixed flow rate out. This is to determine the time it takes to hit a ...
0
votes
2answers
137 views
Definition of volume of a gas and Amagat's law
How would you define the volume of an (ideal) gas?
I would say it is the volume of the container holding the gas (whether it is a fixed container or a flexible one like a balloon).
However, ...
0
votes
1answer
478 views
What is the physical meaning of divergence? [duplicate]
I want to visualize the concept of divergence of a vector field. I also have searched the web.Some says it is
1.the amount of flux per unit volume in a region around some point
2.Divergence of ...
0
votes
1answer
63 views
PV diagram of pure substance
Why does the specific volume of saturated solid state of water decreases with increasing pressure and the specific volume of saturated liquid wrt vaporisation increases with pressure? Can anyone ...
0
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2answers
67 views
Does Avogadro's law only apply to ideal gases?
I know the ideal gas law may change a little when for real gases or diatomic ones does Avogadro's law change too or does it stay the same?
