Ideal gas Definition and 823 Threads

Homework Statement A weather balloon is filled with Helium gas and released from the ground. It goes up 18km and achieves a diameter of 15m. Determine if the following values are greater than zero, less than zero, or equal to zero: ΔV, ΔP, ΔT, ΔU, ΔH, Ssys, surr, Stot Homework Equations ΔU =...

Problem statement, work done, and relevant equations: One mole of ideal gas is initially at 1 atm and has a volume of 5L. a) Calculate the work done on the gas during an isothermal, reversible compression to a volume of 2L. ##W_isothermal = - \int_{v_i}^{v_f} p dv = - \int_{v_I}^{v_f}...

When the ideal gas entropy is derived, we consider N atoms in a box of volume=Lx*Ly*Lz. Then, we make the assumption that Lx,Ly,Lz >>de Broglie wavelength of atoms. I am not sure why we need to make this assumption? Thanks!

Homework Statement Ethanol evaporates in a 10 x 20 x 50 ft3 room. Air is initially dry at a temperature of 30 °C and 765 mmHg of pressure. a) If the partial pressure of ethanol after vaporization is 40 mmHg, how many pounds of ethanol evaporated? b) The same air is compressed until it reaches a...

I was assigned a problem in my Engineering Thermodynamics class as follows: Problem: An ideal gas in a rigid closed container undergoes isochoric heating from T1 = 27 C to T2 = 77 C. Initial gage pressure is 300 kPa, pressure of surroundings is 1 atm. Find the final gage pressure. The way to...

Homework Statement (Excerpted from a longer, multipart problem but essentially) Show that for an ideal gas, $$ \frac{\partial p}{\partial T}\bigg)_\mu = \frac{S}{V}. $$ Homework Equations • The ideal gas law, of course $$ pV = Nk_{\rm B}T $$ • Pressure, temperature, and chemical potential...

Homework Statement Consider particles in a gas centrifuge. This device is used to separate gases of different molar mass by rotating a cylinder at high rates. Derive two equations: one for the pressure (P) and one for the particle number density (nv) as functions of M, r, w and T, where r is...

Hello PF! Consider the free expansion of an ideal gas. The process occurs at constant temperature, therefore, ΔU = 0, Q = 0, and W = 0. Suppose we are given the initial and final pressures of the gas, and we calculate ΔG = nRT ln(P2/P1). As P2 < P1, ΔG < 0. This is intuitive, as a free expansion...

Homework Statement The temperature of an ideal gas is 00C and the pressure is 1[atm]. imagine every molecule is enclosed in a cube, what's it's side length? Homework Equations PV=nRT Avogadro's number: 6.023E23 The Attempt at a Solution I assume volume of i liter: $$1[atm]\cdot...

does anyone know how to do this question. it feels like there's a part of the question missing as i don't know how to complete the equation The pressure of a fixed mass of gas in a sealed sphere is measured to be 1.02 x 10^5 Pa at a temperature of 253K. Assuming the volume of the sphere doesn't...

Can someone explain me why we could put pi, μi and μiο in this equation: and we get this: (this is The chemical potential of a component in a perfect mixture of ideal gases wher pi is partial pressure)

Homework Statement We have a tube with the top end open and the bottom end closed. There is some oxygen gas in the tube and on top of the oxygen there is 10 cm high column of mercury. The initial temperature is 20oC. Then the tube is flipped over and heated to 40oC. The column of mercury shifts...

We know that one model for ideal gas is monoatomic gas with no attractive force between atoms, elastic collision and some other assumptions. I would like to ask if there exist a gas behave exactly the same but the only difference is it's a diatomic gas (or more complicated structure), should it...

can someone help me .In this video from 2.00 to 3.00 how the velocity vector drawn with red color can be broken into x-y-z components and why after bouncing back only x component of velocity changed and y ,z components remained same?

Homework Statement A spherical air bubble in a lake expands as it rises slowly to the surface. At the point it starts to rise, the pressure is 2.00 atm, the temperature of the water is 10.0 ∘C, and the radius of the bubble is 5.00 × 10^−3 m. At the surface, the pressure is 1.00 atm and the...

Considering a unit mass of an ideal gas in a cylindrical container of volume 'V' at temperature 'T' the pressure exerted by the gas at the walls of the container is given by the ideal gas equation as, pV=RT where 'R' is the characteristic gas constant for the particular gas. Under equilibrium...

How do you calculate the entropy of an ideal gas with n = 1, Cv,m = 1.5R, Ti = 300K, P=3bar and expands against Pext = 1bar until final volume is twice initial volume at Tf = 200K?

A Monatomic gas passes from state 1 (pressure p1, volume V1) to state 2 (p2, V2). Derive an expression for the change in entropy of a monatomic ideal gas. The required final equation is: ΔS = Cv ln(T2/T1) + nRln(V2/V1) In my attempt, I am retrieving ΔS = Cv ln(T2/T1) + Rln(V2/V1) i.e.; the...

Homework Statement Determine how many grams of Mg must react with HCl in order to produce 40 mL of hydrogen gas at 22 degrees Celsius and 1.02 bar. Also, If the Mg ribbon weighs 0.836 mg/mm, how many mm of the ribbon will you require? Homework Equations PV=nRT Mg(s) + 2HCl(aq) -->...

Homework Statement a ideal monoatomic gas initally has a temperature of 315K and a pressure of 6.87atm . It then expands from a volume of 440cm^3 to volume 1550cm^3 . If the expansion is isothermal, what is (A) the final pressure (in atm's) and (B) the work done by he gas. Homework Equations...

Homework Statement At an altitude of about 10 km, the temperature of the Earth’s atmosphere is roughly -50°C and the air pressure is around 16 kPa. (Assume ideal gas) How many kilograms of hydrogen gas (H2, molecular mass 2g/mol) should be put in a balloon to fill it to 2000 m3?What is the...

Homework Statement Initial pressure: 140kPa Temperature: 25C or 298K Volume: 0.14m^3 Final Pressure:1.4MPa or 1400kPa It uses index compression, n=1.25. So PV^1.25 = constant. c_p = 1.041kJ/kg.K and c_v = 0.743 kJ/kg.K Homework Equations ¥ = c_p/c_v ΔS=c_v*ln(Tf/Ti) + R*ln(Vf/Vi) [i...

Homework Statement Consider an ideal gas with C_V=6.76 \frac{cal}{mol \cdot K}. Calculate \Delta H and \Delta U when ten moles of this gas are heated from 273.15 K to 373.15 K. Homework Equations \Delta H = \Delta U + P\Delta V Q=n C_V \Delta T The Attempt at a Solution As I'm given the heat...

Consider an ideal gas. For a polytropic process we have ##PV^n = const##. Different values of ##n## will represent different processes; for example isobaric (##n=0##), isothermal (##n=1##), and isochoric (##n=\infty##). The Wikipedia article on polytropic processes states that the specific heat...

I am teaching myself Stat Mech / thermo from Swendsen's "An Introduction to statistical mechanics and thermodynamics". To this point I find the book interesting and clear to follow. But in section 4.6, Probability and Entropy, he confuses me by concluding that the entropy that he defines there...

Homework Statement A mass of gas at an initial pressure of 38 bar, and with an internal energy of 1400kJ, is contained in a perfecty insulaed cylinder of volume 0.06 meters cubed. the gas is allowed to expand behind a piston until its internal energy is 1300kJ. the law of expansions is...

I don‘t understand one step in derivation of ideal gas chemical potential. Generally Gibbs free energy is: (1) (2) We observe that: (3) From equation (3) we make differential equation and integrate it: (4) (5) We get Gibbs free energy dependence on pressure...

Hello everyone, I have an rather large piston-cylinder containing gas that is compressed when the piston extends. Using three sensors I am measuring the pressure, temperature and volume of the gas while I force the piston out using a winch. The system is closed and no gas is released or added...

Homework Statement When 120J of heat are added to this gas, the temperature of the gas changes. Find the change in temperature if the heat is added at (a) constant volume. (b) constant pressure. Homework Equations The equation of state of at the gas is (p + 50)V = 10T The...

Homework Statement A can which is sealed of a volume 0.035m3 contains an ideal gas with a pressure of 150kPa, at a temperature of 350K. Calculate the gas density and the root mean squared speed of the gas molecules (P.S. the molecular mass is stated as 28) Homework Equations...

Homework Statement Hi I am new to Physics Forums and desperately need some help! This is my first class back since undergrad and my math skills have gotten a little rusty. I think that's where I am failing. Okay here goes: http://tinypic.com/r/2zqf04k/8 There is a 4 subsystem...

Homework Statement Two interconnected tanks are of equal volume. One is filled with methane at 500bar and 293K, the other is initially evacuated. A valve connecting the two tanks is opened only long enough to allow the pressures to equilibrate. If there is no heat transfer between the gas and...

I solved the problem myself immediately before anyone replied.

Homework Statement for one mole of an ideal gas this relation holds good P= P0 /{1+(V0/V)^2}, where P0and V0 are constants, what will be its change in temperature in terms of P0,V0 and R, if volume is doubled? Homework Equations for one mole of ideal gas we know PV=RT Then...

Homework Statement Imagine a graph of pressure in kPa (y-axis) against volume in L (x-axis). There is a straight line moving from point A at 300kPa, 0.5L to point B at 500kPa, 1L. The false origin on this graph is 200kPa, 0L. What is the work done by the gas? Homework Equations W=pV...

Consider a system of volume V and pressure P ,if i add molecules of gases in the system while keeping its volume constant and not providing any energy nor absorbing energy from the system ,its pressure will increase and so does its temperature Why does the temperature increase? More molecules...

1. Gaseous compound Q contains only xenon and oxygen. When 0.100 g of Q is placed in a 50.0 mL steel vessel at 0 °C, the pressure is 0.229 atm. When the vessel and its contents are warmed to 100 °C, Q decomposes into its constituent elements. What is the total pressure, and what are the partial...

Homework Statement A small sphere, with initial temperature ##T##, is immersed in an ideal Boltzmannian gas at temperature ##T_0##. Assuming that the molecules incident on the sphere are first absorbed and then re-emitted with the temperature of the sphere, determine the variation of the...

An ideal gas is placed in a tall cylindrical jar of crosssectional area 0.080m^2. A frictionless 0.10kg movable piston weight is supported by the gas pressure in the jar. When the gas is heated (at constant pressure) from 25C to 55C , the piston rises 1.0cm. How much heat was required for this...

Given that U = (3/2)PV does this mean that ΔU = Δ(3/2)PV for an ideal gas? Hence when finding the change in internal energy using a P-V diagram, can we simply apply this equation instead of using ΔU = Q+W?

Hello all, As part of a research project, I am trying to calculate the amount of water/dry ice I would need to put in a cylindrical pressure vessel to obtain an internal pressure of ~100 psi at 200C (from room temperature, ~23C). I haven't had to do a calculation like this in awhile, but...

Why the kinetic energy is same as internal energy of ideal gas?

okay so I suck at La-Tex so I'm not going to put the actual equation, but it's not important for my question. In the equation the entropy is dependent on the natural log with mass in the numerator of the argument. Why is mass involved when talking about entropy at all? I mean I think of...

In the semi-classical treatment of the ideal gas, we write the partition function for the system as $$Z = \frac{Z(1)^N}{N!}$$ where ##Z(1)## is the single particle partition function and ##N## is the number of particles. It is semi-classical in the sense that we consider the...

Hi everyone. I thought of a question which has been bothering me. It is: Is there a case where energy is added to an ideal gas of constant amount where the energy added will equal the work done by the gas. My thoughts: The energy of an ideal gas is proportional to the temperature. If the...

Is the following approach used for the derivation of the ideal gas equation correct? Here's the link: http://www.mikeblaber.org/oldwine/chm1045/notes/Gases/IdealGas/Gases04.htm

Hello, I am wondering, if you have an ideal gas mixture, does that automatically mean that the solution is an ideal solution? Or is it possible to have an ideal gas mixture that is not an ideal solution. Thanks

I have read that enthalpy of an ideal gas is a function of temperature only, I am having a little trouble getting it. Consider a cylinder filled with an ideal gas so if we increase the pressure by pushing the piston down on it , a/c to ideal gas equation the temperature also rises, which in...

Hello Homework Statement From the expression of the partition function of a fermi dirac ideal gas ln(Z)=αN + ∑ ln(1+exp(-α-βEr)) show that S= k ∑ [ <nr>ln(<nr>)+(1-<nr>)ln(1-<nr>) Homework Equations S=k( lnZ+β<E>) <nr>=-1/β ∂ln(Z)/∂Er <E>=-∂ln(Z)/∂β The Attempt at a Solution I...

Homework Statement A cylinder fitted with a movable piston contains ideal gas at 27C, pressure .5 x 10^5 Pa, and volume 1.25 m^3. What will be the final temperature if the gas is compressed to .8 m^3 and the pressure rises to .82 x 10^5 Pa. A) 125 C B) 154 C C) 246 C D) 67.7 C E) 41.8...