Gases Definition and 501 Threads

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...

Alright, ASSIGNMENT it is required of me to to the physics part in a group project where the topic is "causes of global warming". my group has chosen methane clathrates or methane hydrates if you like (in the ocean, not on land). The way these work is that it is methane gas that is trapped in...

Homework Statement From Giancoli's UC Berkeley edition Physics for Engineers and Scientists: A 2.00 mole sample of N2 (nitrogen) gas at 0 degrees C is heating to 150 degrees C at constant pressure (1.00 atm). Determine the heat added to it.Homework Equations Variables in equations: V = volume...

Hi Everyone, I have a problem that I've been working on and I'm having a little trouble. Essentially I have a tank with a known leak rate at a given pressure and temperature. We are currently using hydrogen, but I need to know what the equivalent leak rate would be if we changed the gas to...

Bernoulli's equation as I understand it is an expression (or possibly a consequence) of conservation of energy in an incompressible fluid flow. My question is: how can the "standard" Bernoulli's equation ever apply to an ideal gas? Wikipedia gives a different version of Bernoulli's...

Here are some general questions regarding my current reading. I am looking in my text at 2 equations for specific energy and specific enthalpy: u = u(T,v)\qquad(1) h = h(T,p)\qquad(2) Question 1: Are not the properties fixed by any 2 independent priorities? Why have we chosen to...

Hi all, I've been playing around with chloroammine gases and have been trying to react them with solids [with some success, but I don't think it is as efficient as I would like]. I am producing a mixture of NH3, NH4Cl, NH2Cl, NHCl2. The ammonia I am not worried about, what I am wanting to do is...

Homework Statement not really a question, just stuck with something. An airflow of 300 CFM has a contains 0.0387% CO2 (carbon dioxide-naturally occurring in air) flows through two ends of an rectangular open container from an exhaust fan located at the bottom. Within the container 100%...

For an isochoric process, dV = 0 therefore dW=0 So from 1st of Thermodynamics, dQ = dU + 0 or, n*Cp*dT = n*Cv*dT (Cp and Cv denote molar heat capacities of the gas at const pressure and volume resp.) therefore we get Cp = Cv .(how can this be possible once we know Cp - Cv = R ?)

Homework Statement A scuba diver releases a 2.50-cm-diameter (spherical) bubble of air from a depth of 11 m in a lake. Assume the temperature is constant at 16.0ºC, and the air behaves as a perfect gas. How large is the bubble when it reaches the surface? Homework Equations V2 = V1*(T2...

Question:Dalton’s law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of gases making up the mixture. Give a convincing argument for this law based on the kinetic theory of gases. Answer to this question from the book I...

I read somewhere that a special fluid, called hydrofluorocarbon, is used in refrigerator. It carries hot temperature from the refrigerator and put it out. They says that it has a low specific heat capacity and low liquid/gas transition point (room temperature). Now my question is why ideal gas...

Hi, I was wondering what effects pressures (>100bar) would have on half-cell reactions. Normally, I'd use the Nernst Equation, but under immense pressures the value "R" is no longer ideal (pun intentional). The electrical pressure (voltage) goes up because (I would assume because) the number of...

I have a question about how to calculate the mass/mole of a combustion gas. In my own research, I came across two methods. The first method is suspect in my opinion. The second I trust, although the discussion left some issues unexplained, so I attempted to fill in the details as best I...

A rocket with initial mass of 7.30×103 kg is fired in the vertical direction. Its exhaust gases are ejected at the rate of 6.00×101 kg/s with a relative velocity of 2.100×103 m/s. What is the initial acceleration of the rocket? What is the acceleration after 29 s have elapsed?

Note: This isn't intended to be a Global Warming thread but rather a Greenhouse Gases thread (they're not the same thing), so please let's not talk about Global Warming because I don't want it closed. I'm very interested on any feedback or thoughts anyone may have for my experiments...

Hey I'm studying the Kinetic Theory of gases and although it's in a chemistry book it employs physics concepts ergo I have come here to ask you nice people :biggrin: The 5th point is where I have a problem, the rest is just information for you. I am assuming a particle is in a cube (ideal...

first i want to apologize if I'm posting this in the wrong section. my first post here. I know that all gases expand at the same rate at consistant pressure when heated. My question is do different gases expand at different volumes under equal pressure and heat? If so what would be some...

Homework Statement Containers A and B in the figure hold the same gas. The volume of B is four times the volume of A. The two containers are connected by a thin tube (negligible volume) and a valve that is closed. The gas in A is at 300 K and pressure of 1.0*105Pa. The gas in B is at 400 K and...

Homework Statement In the gas phase methyl isocyanide (CH3NC) isomerizes to methyl cyanide (CH3CN) in a first order reaction with a rate constant of 7.70x10^-4s^-1 at 500K. An experiment is performed, where 25.0 torr of methyl isocyanide is placed in 23.2L container at 500K. After 520...

Homework Statement The Stephan Boltzman Law used in black body cavity situations is sometimes used when dealing with gases, is this a valid use of the equation? Homework Equations H=AekT^4 H is heat current in radiation A is the area e is the emissivity k the Stephan Boltzman...

Calculate the heat capacity ratio for a diatomic ideal gas. ---- Using the equipartition theorem, I calculate: Cp / Cv = (Cv + R) / Cv = (7/2 R + R) / (7/2 R) = (9/2 R) / (7/2 R) = 9/7 ~ 1.286 According to the equipartition theorem, I assign each vibrational degree of freedom 1 R and...

Happy New Year to all you Physics Geniuses out there! I have a question concerning how the optical emission spectrum of a gas would be affected by being dissolved in water. I know very little about spectroscopy so please forgive me if this seems like an idiotic question. Let's assume I...

Hello every one :) Actually i was studying from Charles Kittel ( introduction to solid state physics ) about crystals of inert gases , then i asked my self how could inert gases forms a crystals , i couldn't answer that , and no place to read about it :( . So can you people...

Hunting season has arrived where I am located and I have had to choose a bullet/cartridge combination to hunt with. To do this I had to decide what range I would likely shoot, how much drop or drift I was willing to tolerate, the amount of recoil I could handle and lastly would the kinetic...

Two separate flasks are each filled with a gas at 25 degrees Celsius; the valve between them is opened and the gases are allowed to mix. What would be the final pressure in torr after mixing, if initially F2 is in the first flask (Volume = 2 L) at 271.78 torr and N2 is in the second flask...

Homework Statement At 318 K and 1.04 x 10-2 atm, the density of a gas is 1.75 x 10-5 g/cm3. (a) Find vrms for the gas molecules. (b) Find the molar mass of the gas. Homework Equations vrms= sqrt (3RT/M) pV=nRT pM=dRT pV=(m/M)RT The Attempt at a Solution the main problem i...

Homework Statement 3.50 g of magnesium metal is added to 100. mL of 2.00 M aqueous hydrochloric acid. The substances react to completion, producing aqueous magnesium chloride and hydrogen gas (H2). How many liters of pure hydrogen gas, measured at 0.00oC and 1.00 atm are produced in this...

Relations for an ideal Fermi gas: \frac{P}{k_BT}=\frac{1}{\lambda_D^3}f_{5/2}(\lambda) \frac{1}{\upsilon}=\frac{1}{\lambda_D^3}f_{3/2}(\lambda) But in some book books I find \frac{P}{k_BT}=\frac{g}{\lambda_D^3}f_{5/2}(\lambda)...

Hello everyone, The partial pressure of the atmosphere 33 feat benath the surface is doubled the normal amount. (2x760 mmHg). I can understand how lower you go down higher the pressure but I don't understand how you can measure atmospheric pressure under the sea. I mean under the sea you got...

Hello everyone, Ok to understand the respiratory system, proper understanding of this diagram is essential. Something I don't have, so if anyone can help me with these questions I would be very greatful. Thanks :smile: http://img515.imageshack.us/img515/8923/rightbv.jpg 1. Anatomic dead...

I've been told that gases take on the volume of whatever container they're in but what about Pv=Nrt ? Would it be possible that the calculated V is smaller than the container's volume? Thanks

Hi, Anyone know where I can find thermodynamic properties of gases at high pressure? More specifically I need to find the kinematic viscosity or the absolute viscosity of air at around 300 degrees Kelvin and 330 bar. Cheers

3 Gases On a Graph, Which is True ?? Homework Statement http://img103.imageshack.us/img103/9302/spdistus8.jpg Based on the distributions show above, which statements for the three gasses I II and III are true? Note that the temperature is constant for all three. a) Gas III is the heaviest...

Good morning, (This is not homework; just curiosity) I found a little problem concerning Theory of Gases. I was able to solve it, but I want confirmation about if this is correct or not. Homework Statement Suppose I have a cube-shaped box, with edges measuring 20 cm = 0,2 m, which...

Homework Statement Consider a mixture of oxygen and hydrogen kept at room temperature.As compared to a hydrogen molecule an oxygen molecule hits the wall- (a) with greater average speed (b)with smaller average speed (c)with greater average kinetic energy (d)with smaller average kinetic...