Gases Definition and 476 Threads

For a non-ideal gas expanding in a vacuum, the kinetic energy of each of the molecules does NOT remain consant as the gravitational effect of the other molecules would "slow down" these velocities by deceleration. What are those forces referred to? Are they "Newton" forces or what? I can't...

Homework Statement See attachment ecxample001. Homework Equations See attachment D11. The Attempt at a Solution In the first equation (Cp/R = a+bT+cT^2...etc.), Cp/R is the constant pressure specific heat. The general formula for enthalpy change is h2-h1 = integral[Cp]dT, so does...

hi.. please tell me that 1) why some materials like ZnO, SnO, Pt, etc r sensitive to gases and others like Si, Ge, InP, GaAs, etc r not sensitive to gases. 2) how doping increase the sensitivity of a certain material to certain gases.

How the current Flows from gases ?

Hello,world 1-"the intermolecular attractive forces between gas particles are very weak due to the large intermolecular distances separating them" Is that true? this is wriiten in my textbook and it is confusing me because I've always thought of it in a different way ,I thought the...

I have reviewed recently the demonstration of the formula for the pressure of a gas by using the kinetic theory and it seems that there is a terrible flaw in it, which I will describe below. Can anyone comment on it, please? In all textbooks, the pressure of a gas is proven to be proportional...

Hi, I have a conceptual and mathematical question about gases in stars. The information we have from stars is due to the motion of particles in one dimension: along our line of sight. We assume that this motion is isotropic and that regardless of where on the star we look, we'll get the...

Hi, I have a conceptual and mathematical question about gases in stars. The information we have from stars is due to the motion of particles in one dimension: along our line of sight. We assume that this motion is isotropic and that regardless of where on the star we look, we'll get the...

On the way into work, I pass through "Hospital Alley". I saw a collection of Praxair tanks with radiating fins that were covered in ice. If you put fins on something that's cold, it will warm up faster. I was trying to figure out why they would have a system that was designed to warm up the...

A rigid tank with a volume of 0.75 m3 initially contains air at 70 kPa and 25 degrees C. A small hole develops in the tank. The surrounding air at 100 kPa and 25 degrees C slowly leaks into the tank due to the hole. Heat transfer between the surroundings and the tank maintains a constant air...

Hello, So, I am reading this theory, and I come across this sentence explaining to me that gas particles of different mass have the same average kinetic energy at a particular temperature. Is this somehow due to momentum? Each particle is given a certain energy which will cause them to move...

Hi. Consider a plenum with a small restricting outlet. Highly heated gas constantly flows through the plenum, and a build-up, or congestion of high-pressure gas exists in the plenum due to the restricting outlet pipe. The intake flow of gas does not change. 1. A hotter plenum should...

Okay, I have searched the internet for why one mole of any gas occupies the same volume, and found the internet devoid of any explanation that will suffice in my understanding. Can someone please help me Thank you

hi everyone, consider two different masses of ideal gases with different molar masses, we're putting them in a uniform gravitational field and wait until they come to their equilibrium states. how would the density distribution change with height in this case? ( i came out with this question...

Homework Statement I know how to do the problem so I don't need help actually solving it, I just don't understand the concepts. A sample of 4.5g of methane occupies 12.7L at 310k. a) Calculate the work done when the gas expands isothermally against a constant external pressure of 7.7 kPa...

Hello everyone. I would like to know if I did this correctly. Homework Statement Calculate the heat, internal energy and work of 1 mol of hydrogen, which undergoes a reversible adiabatic expansion from a volume of 5.25 m^3 at 300 K to a volume of 25.5 m^3 The Attempt at a Solution...

The main book we'll be using will be Serway's, but I want a different book that's more focused on the mathematics formulation of thermodynamics and kinetic theory of gases, and not so simple as Serway's. The other 3 books in the discipline's bibliography are: • M.W. Zemansky and R. H...

Calculate "a" values given equation of state for gases Homework Statement For my equation of state: Vm = (RT/P) - (a/T) what kind of sign for the constant a (positive or negative) do you think the following gases will have and why: a. H2 b. He c. CH4 d. CO2 Hint: There is almost no...

Homework Statement Two monatomic ideal gases are separated in a container by an impermeable wall, with volumes V_{1} and V_{2}, temperatures T_{1} and T_{2}, number of atoms N_{1} and N_{2}, and both are at the same, constant pressure P. The wall is then removed, and the pressure is continued...

I think most of us have probably seen the little trick in which somone will place a burning candle in a bottle and get something like an egg to be pushed inside the bottle. How does this happen? I understand that a vacuum is created inside the bottle, and the normal outside air...

Homework Statement From the book: "When electrodes are placed in a gas at normal atmospheric pressure no current passes and the gas act as an insulator until the electric field is increased to above 3 or 4 MV/m when sparking takes place. In crontast, at lower pressures, a steady current can be...

I've never known this but the equation only seems to contain a conduction term so I assume it can only apply to solids. Is there a similar equation for the time-evolution of temperature fields in gases, where convection is also considered? (how about radiation? although that sounds like it will...

Hi I would like to ask is there any relation between compressibility factor of gases and temperature? My textbook says that it always increases with increase in temperature but doesn't explains how? I know that on increases the temperature it is harder for molecules to show attractive...

Hi guys, I am designing a mixing box for different gases. Here is my plan: I will use Acrylic panels with the dimension of 30cm x 30cm x30cm. Two 3/4 inch pipes feed inflows at flow rate of 1300 LPM in total. The outlet is an rectangular opening of 8cm x 8cm. How can I define the pressure inside...

If the aleatory speed of a gas rises with pressure and temperature and there is not an apparent limit for these two, what prevents the particles to reach the speed of light? thank you

I'm going to be very careful to avoid the word "greenhouse" because of the indefinite ban on discussions about climate change - I want to be clear, this isn't a topic about that. Part 1 - some gasses in the atmosphere absorb and emit radiation in the thermal infrared range. Gases like water...

i have a question that I cannot solve; Show that the rms velocity of a sodium atom moving in a vacuum chamber at 300 kelvin is about 570 metres per second pV=nRT and 3pV=Nm<c^2>

Homework Statement One mole of an ideal gas does 1975 J of work on the surroundings as it expands isothermally to a final pressure of 1.2 atm and a volume of 24 L. find the initial volume. The universal gas constant is 8.31451 J/K mol The Attempt at a Solution Something he...

in the picture you can see Three different tanks contain Three different gases. the temperature are equal to 25 Degrees Celsius in all the Three tanks, and it not changing. i asked to calculate the kinetic energy of the Three different gases. so i thought to use this formula:3/2*RT but i...

final pressure when two gases at different pressure are mixed. The valve between a 5-L tank containing a gas (Methane) at 3 atm and a 1-L tank containing a gas ( Ethane) at 0.55 atm (both are in 50 Degrees Celsius) is opened. What is the final pressure in the tanks? (assume that there is no...

I just have a question of this subject, it is a pretty straight forward concept, however there are things that i just can;t figure out, like in any given gas which is the minimum volume required to have a maxwell boltzman distribution, @ 1 atm 273.15 K ? I honestly just can't figure it out...

As a hobby, I have been researching the different aspects of modeling the sounds produced by musical instruments. Particularly, I want to create as accurate a model as possible, and not something very simple (to which many may ask "why?" if complexity will reduce the likeliness of real time...

Two gases are in a vessel and separated by a partition. They start at different pressures P1 and P2. When the partition is removed and equilibrium restored am I right in thinking the new pressure is the average of the starting pressure i.e. P_{f} = \frac{P1+P2}{2} Thanks.

Hello Forum, Does anyone know where I can find the slater bases for the alkali metal 'np' orbitals and the noble gas '(n+1)p' orbitals, either altogether or individually? I'm a physicist and wanted to know what the standard (or even non-standard) reference is? I know that the...

Homework Statement A volume of 2.40x10^-3 m^3 of hydrogen gas is enclosed in a cylinder with a movable piston at 300 K under a pressure of 203 kPa (2.00 atm). The density of hydrogen under these conditions is 0.180 kg m^3. 1. The gas is cooled down to 150 K, and the pressure is increased to...

PLEASE someone explain me in detail why gases cool on expansion? yOU may say that when they expand work is done at expense of internal energy but why? Wat is the need to do work when they are not forced to , I mean when they are not given external energy... Someone please explain the concept to...

Homework Statement The volume of air taken in by warmblooeded vertebrate is 250 L/day at standard temperatutre and pressure (0 Degrees C and 1 atm). If air in lungs is at 43 degrees C under pressure of 440 mm HG and we assume vertebrate takes in average volume of 100cm cubed per breath at...

Homework Statement What happens when gas is heated? Is all of the absorbed energy converted to kinetic energy? or is some of the absorbed energy converted into potential and some into kinetic energy? Homework Equations The Attempt at a Solution My teacher said the correct answer...

I have to mix 2 gases, Hydrogen and Nitrogen to achieve a constant flow of mixed gas with 100, 200... 1000 ppm of H2 in the mixture. I have mass flow meters to adjust the flow of each individual gas but how do I determine what they should read to achieve the desired ppm

I have some questions on kinetic theory of gases: kinetic theory assumes that the inter molecular force of attraction between two molecules of a gas is negligible. This assumption applies to the condition that the said gas is either at low pressure or at high temperature. This means, when the...

If we can heat a gas so that the electrons "fly" off, can we heat one so that the protons do?

I'm working on a model that needs to calculate the approximate thermal conductivity of a mixture of gases. I'm having trouble finding a model which is being used by one of my sources but is not cited and I can't seem to find a source for it. I'm hoping that someone here might recognize the model...

Hi! I have two multiple choice question which I'm having trouble solving. 1) Why do all elements (except rare gas atoms) seldomly close pack as much as the rare gas atoms although they attract each other much more. i. Too much attraction deforms the crystal structure ii. It is due to...

Why does the ideal gas state equation fail at high pressures for real gases? I think it has something to do with the forces between the molecules in the gas, but I'm not sure the exact reason

Hello. There is something I don't understand about the momentum tensor t_{ik}=nm\int f(|v|) v_iv_k of an ideal gas with an isotropic velocities distribution where n is the number of molecules per unit volume and m is the mass of a molecule. Since the the velocity distrubution is isotropic...

Can the density of gas be changed for good, or is the change just temporary? And what increases density in gases?

Hello colleagues, I have a seminar that i need to turn in a weeks day from now. My professor listed the following questions, guidelines that I should lean on: 1) Is it possible to achieve a temperature bellow absolute zero (-273,15) 2) An ideal gas contracts linearly when decreasing...

Homework Statement An ideal monoatomic gas is confined in a cylinder by a spring-loaded piston of cross section 8 x 10-3m2. Initially the gas is at 300K and occupies a volume of 2.4 x 10-3 m3 and the spring is in its relaxed state. The gas is heated by a smalll heater until the piston moves out...

Homework Statement The reaction of 50 mL of H2 gas and 50 mL of N2 gas via the equation: 3H2 + N2 ---> 2NH3 will produce how many mL of product? A reaction of 25 mL of Hydrogen gas and 75 mL of Nitrogen gas? Assume that temperature and pressure are constant. Homework Equations...

When I took AP Physics we did similar problems... almost identical lol Homework Statement http://img252.imageshack.us/img252/6931/chemistry.jpg Uploaded with ImageShack.us Homework Equations SEE BELOW The Attempt at a Solution...