Gas Definition and 1000 Threads

How can I see, by looking at a band structure if the substance in question can be viewed as a free electron gas (FEG) or not? What characterizes a FEG in a bandstructure plot? Thanks in advance!

My concern is an electron tube. From what I understood so far, gas molecules will have an average velocity derived from the Maxwell distribution, and that velocity will influence in the electron collision frequency. I can't see clearly though how the electron velocity itself in the presence...

Hello all. I have a question about gasses and pressure: Is there a way to calculate how strong a material making up a balloon has to be to withstand a given pressure difference between the inside and outside? In other words, if I have a balloon I need to fill to a pressure of 10atm inside vs...

In the derivation of finding pressure exerted by a gas using kinetic theory of gases I am not understanding why the time between two collisions is taken as the time for rate of change of momentum when a particle bounces back from the wall. please help me

I can measure O2, Co2, TGP, and temperature, Want to calculate the rest gases, so N2, and Ar in my water. There for i bulit up an axcel table. So i get to the point to calculate Bunsen contans on different Temperature. I have this calculation: ln(β)=exp(A1 + A2*(T/100) + A3*ln(T/100) +...

Ok, i am struggling to figure something out. I don't know why math is so much easier than physics haha. ok, here is my struggle. I have two states, state 1 and 2, which i will call just 1 and 2. 1: T=298kelvin V=0.025m(cubed) P=310Kpa Mass1=Mass2 R=0.2870 2: T=323kelvin V=0.025m(cubed) P=...

I was assigned an example problem today and i can do the math, look at my tables and get the right answer no problem. What i want to understand, is why when specific volume increases for r134a, that it means its supper heated? My given value for sv was .1384m3/kg which is above the .09 in the...

Homework Statement After a free expansion to quadruple its volume, a mole of ideal diatomic gas is compressed back to its original volume isobarically and then cooled down to its original temperature. What is the minimum heat removed from the gas in the final step to restoring its state...

Homework Statement Homework Equations Ideal gas law The Attempt at a Solution The solution to this problem assumes the pressure inside the balloon is the same as the outside pressure, i.e. atmospheric pressure. Is this a valid assumption? I would guess otherwise.

Homework Statement I have an empty 2-Liter bottle. It contains 3 g of air inside with an initial air pressure of 1105 mb. When I open it (which is an adiabatic process), I release the pressure which is instantaneous. The pressure then becomes standard atmospheric pressure. What is the...

I was reading about the Pendle Hill experiment by Henry Power and Richard Towneley showing the relationship between Volume and Pressure in gas that eventually became Boyle's Law. The higher they got the greater the volume became. My question is, was the gas measured in the barometer isolated...

Homework Statement What is a real-life example of the ideal gas law? Homework Equations PV = nRT (Pressure x volume = number of moles x the gas constant x temperature in Kelvin) The Attempt at a Solution https://www.reference.com/science/ideal-gas-law-used-everyday-life-3dacbd6ebd3b5949...

Homework Statement What is w when a gas is compressed from 42.1 L to 25.1 L using a constant external pressure of 739 Torr? Remember to include a "+" or "−" sign as appropriate. Homework Equations W = -P(dV) The Attempt at a Solution Pressure = (739 Torr / 760 Torr)*(101.325 kPa) W =...

If considering the free expansion of an ideal gas adibatically such that the final volume is double of the initial volume. Since dU=0 for free expansion ,which implies Ti=Tf for ideal gas...(1) From adiabatic relation , TiViγ-1=TfVfγ-1, to satisfy (1) ,γ-1=0 and for ideal gas Cp-Cv=nR or...

Obviously expanding the gas cools it down. I'm interested if you could boil water and then expand the high pressure steam to cool it down to 0°C. Or are there subtler thermodynamics that would prevent this?

A friend of mine and I have been discussing how to apply the first law of thermodynamics to analyze the quasi static expansion of an ideal gas in a cylinder featuring a piston having both mass and friction (with the cylinder). We have identified two different systems that can be used in the...

Homework Statement Homework Equations pV=nRT The Attempt at a Solution I know the volume of the cylinder, which is Al. So I plugged this into the ideal gas law formula, and got answer B. However, the correct answer should be D. I see the Boltzmann's constant there in the equation, and I do...

Hi all, I have a few questions concerning cars and HP, I will post the first question now and I think the answer will determine if I need further help. I will prefeace my question with the disclaimer that I have very limited automotive knowledge. If 2 cars that are operating at the same...

Homework Statement An ideal gas has a molar mass of 40 g and a density of 1.2 kg m-3 at 80°C. What is its pressure at that temperature? Homework Equations PV=nRT R constant= 8.314 n= number of moles T= tempreture in kelvin density=Mass/ Volume The Attempt at a Solution i simply solved it like...

Hi everyone, I'd really appreciate any help with this problem: A helium cylinder for the inflation of party balloons hold s 25.0L of gas and is filled to a pressure of 16500kPa at 15 degrees celsius. How many balloons can be inflated from a single cylinder at 30 degrees celsius if the volume of...

Homework Statement From near to the center of the solar disc, Fe I line emission from point X shows a spectral line with components 666.823, 666.830 and 666.837 nm, around the rest wavelength of 666.800 nm. The central component is not as bright as those at the longer and shorter wavelengths...

I am writing a document on the Joule-Thomson effect. But in my research for it I have come across something that I am not completely clear on. In my document I explained the free expansion of an ideal gas and am trying to transition/segue into the Joule-Thomson effect. However now I am having...

Hello What is the meaning of the average velocity of gas molecules calculated by Boltzmann distribution (in kinetic theory of gases)? Does all molecules have the same average velocity?

I was getting gas today on my way home from work, and the apparatus on top of this box truck parked in the parking lot caught my eye. Just as with unusual antennas, when I see something like this I need to take a closer look to see if I can figure out what it is being used for. (Luckily no...

Homework Statement What is the solubility of an unknown gas in water at 1.0 atm if its solubility at 3.0 atm is 1.02M? Homework Equations Henry's law Sg = k*Pg The Attempt at a Solution Sg = 1.02M/3.0atm * 1.0 atm = .34 atm I'm not sure if Pg, the partial pressure of the gas, is 1.0 atm or...

The ideal gas law is given as ##PV=nRT## where ##R## is said to be the universal gas constant equal to ##0.082056\frac{L⋅atm}{mol⋅K}##. ##R## is said to be a constant, and thus cannot change even if we change the values of ##P,V,n,T##. I don't see how this is possible, because the way we found...

The ans comes out (c) if I take specific heat at constt volume to be independent of temp. Whether the specific heat is always temp. independent for an ideal gas??

I just read a couple articles discussing the surface gravity of Saturn and Jupiter. I would expect the "surface" gravity of these planets to be much higher than that of Earth. I understand how the low densities of these planets has influence on that, but I thought mass was related to gravity in...

If a gas is suddenly allowed to expand freely and adibatically inside a container then from the first law of thermodynamics dQ=0, My question is whether the change of internal energy would be 0 and if it then how would the work done be 0 (since accessible volume of the gas changes inside the...

Hello, I want to develop a pressure regulator model in simscape. The model will be the springloaded direct acting system and the aim is to target outlet pressure, temperature and flow rate by giving input parameters as pressure, temperature, spring stiffness, length and preload, lever(it is...

Homework Statement In the figure below, the volume expands while the pressure is constant. What happens when this gas expands? A) heat is added and temperature increased B) heat is removed and temperature decreasesd C) heat is added and temperature decreased D) heat is removed and temperature...

Homework Statement In a certain process, a gas absorbs Q amount of heat and performs kQ amount of work, the molar heat capacity of the gas in terms of R, k and γ(Cp/Cv) is? Homework Equations U=Q+W U=nCvdT Q=CdT The Attempt at a Solution replacing U and Q with the above formulas and W from...

Homework Statement An adiabatic isolated system is formed of three identical balloons (of unknown volume). The balloons are joined by tubes of negligible volume. Each tube has a faucet/tap that is initially closed. The balloons have different quantities of the same ideal gas. After opening...

Homework Statement In all calculations, take R = 8.31 J/m-K. Use the Sackur-Tetrode equation with N replaced by n and K replaced by R to calculate the changes in entropy. Also, assume that these processes are quasi-static so that the ideal gas law and the first law apply at all times. Consider...

hey! EDIT: I didn’t post this in homework help because there aren’t any computational questions, it’s just conceptual My assignment scenario consists of a star (blackbody) surrounded by an expanding shell of hot gas. I’m given its spectrum and it is a continuous emission spectrum. Emission...

What is difference between perfect gas and ideal gas?

Hello, Assuming that dust is formed by silicates with Mg and Fe. What is the largest possible silicate dust-to-gas ratio in mass?

The MB energy distribution is: MB_PDF(E, T) = 2*sqrt(E/pi) * 1/(kB*T)^(3/2) * e^(-E/(kB*T)) How do I arrive at the density of states which hides inside the expression 2*sqrt(E/pi) * 1/(kB*T)^(3/2) ? I've only seen DOS that have "h" in them.. I want it to contain only E, pi, kB and T.. This is...

What could be the method for measuring weight of gas in inflated balloon? Thanks & Regards, Prashant S Akerkar

I attend a trade school, majoring in HVAC (Heating, Ventilation, and Air-Conditioning). My instructor has given me information that seemingly contradicts what my textbooks tell me about Charles' Law. My instructor is not a scientist. I asked my instructor to reconcile the two seemingly...

Homework Statement The following is the equation of ideal gas law, where p is pressure (Force/Area), V is volume, n is number of moles and T is temperature in Kelvin. What is the fundamental unit of R? pV = nRT A. kg^−1 · m^−2 · s^ 2 · K · mol B. kg^−1 · m^−4 · s ^2 · K · mol C. kg · m^4 · s...

Hello, I am trying to figure out where my reasoning falls apart in this thought experiment: To determine if a process "A" is reversible (or at the very least internally reversible), I try to picture a reversible process "B" that involves only heat transfer and links the same two endpoints that...

I'm looking for advice on how much power is required to compress air in a gas turbine engine - parameterised by degree of compression and mass flow. Normal gas turbine engines have exhaust turbine(s) on the same shaft as the air compressors. They bleed some of the exhaust energy to drive the...

Homework Statement The question is: One kilogram of a gas with a molecular weight of 35 is contained in a balloon. The initial conditions are 27 C and 0.025 m^3. The gas is slowly heated isothermally until the final volume is 0.05m^3. The atmospheric conditions are 100 kPa and 27 C. The p-v-T...

In general, when we say that in a fermionic gas the higher its density, the better we can consider it to be a plasma instead of gas?

Hi, Can some one point me to where I can workout the amount of force required to compress a niitrogen filled ram. Ram has an 80 mm bore and 172 mm stroke. We have filled it with nitrogen to both 1 and 1.5 bar. thanks Brett

When do we use the equations of curvature drift ( ΔΒ⊥Β) V∇B= ±1/2u⊥rL (B x ∇B)/B2 and the general VF= c/q (F x B)/B2? For particles like muons and protons, do they need different equations to calculate a gas' drift velocity, when the gas is made of protons or muons instead of electrons? Am I...

When do we use the Boltzmann equation for density in a Fermi plasma? n in [cm-3] and when do we use the ρ=m/V, ρ in [Kg/m3 ] (this is not an example, I just added the equations to make my question more understandable) Is the ideal gas only when we have electron and ions? Is the Boltzmann...

When an ideal gas,in a piston kind of system and whose equilibrium state is mentioned, is allowed to expand (piston is allowed to move and not gas leaking )against a constant external pressure very quickly, then, is the work done by gas zero or not zero ? The argument for work being zero is...

Homework Statement Basically the units of the Canonical Partition Function within the logarithms should be zero Homework Equations The Attempt at a Solution N here is a number so we ignore the left logarithms, applying a "Unit function " for the terms within the logarithm...