Ideal gas Definition and 856 Threads

  1. W

    Understanding the Ideal Gas Law: State Changes and Work Calculation | Geocities

    The diagram below shows state changes of an ideal gas. The temperature of states (1), (2), (3) are T_1[K], T_2[K] and T_3[K] respectively. The state change from (1) to (2) is an adiabatic change (not an isothermal change). The state change from (2) to (3) is a change at constant pressure...
  2. K

    Question about the ideal gas law

    Hi, I have a question about the ideal gas law. I have been under the impression that if volume goes down then pressure and temperature go up. But, if you look at the equation T=PV/nR, it seems that if volume, say, doubles, pressure will be halved and vice-versa. While that makes sense, it...
  3. A

    What is the relationship between bulk modulus and pressure in an ideal gas?

    The questions is that The equation of state (the equation relating pressure, volume, and temperature) for an ideal gas is pV=nRT, where n and R are constants. a.) Show that if the gas is compressed while the temperature T is held constant, the bulk modulus is equal to the pressure. b.)...
  4. V

    Kinetic-Molecular Model of Ideal Gas: vrms/vav

    Hey, This should be a pretty simple problem to answer... I'm just a bit confused on this, and want to make sure I'm right. It's an easy problem: Molecules in a gas can only move in the x direction (i.e., v_{y}=v_{z}=0). You set up an experiment in which you measure the velocity of a few...
  5. Q

    Once more with feeling another ideal gas question.

    [SOLVED] once more with feeling! another ideal gas question. the pressure inside a sealed can which is kept in a deep freeze at -23C is 0.8x10^5 N/m^2. If the can is placed in water of temperature 27C: calculate the increase in pressure inside the can. initially, pressure/temperature =...
  6. L

    Finding Temperature Using Ideal Gas Law

    The pressure in a constant-volume gas thermometer is 7.09x10 to the fifth power Pa at 100.0 degrees celsius and 5.19 x 10 to the fourth power Pa at 0.0 degrees celsius. What is the temperature when the pressure is 4.05x10 to the third power Pa? now I've been told how to do this problem many...
  7. A

    What is the Tire Pressure After Temperature and Volume Changes?

    here's another one that stumped me An automobile tire is inflated with air originally at 10C and normal atmospheric pressure. During the process the air is compressed to 28% of its original volume and the temperature is increased to 40C. a) what is the tire pressure? b) after the car is...
  8. C

    Adiabatic Process for an Ideal Gas

    During the compression stroke of a certain gasoline engine, the pressure increases from 1.00 atm to 20.3 atm. Assume that the process is adiabatic and the gas is ideal with (gamma)= 1.40. (a) By what factor does the volume change? Vfinal = (ans)*Vinitial (b) By what factor does...
  9. S

    How Does Pricking a Balloon Affect Entropy in an Isolated System?

    we have an evacuated thermally isolated chamber with a balloon inside. the balloon is filled with a volume V1 of an ideal gas at pressure P1 and temperature T1. the balloon is pricked so that the gas fills the chamber. we have to find the entropy change of the system. I'm not sure if we can...
  10. M

    Temperature Variations of Ideal Gas in Gravitational Field

    Could somebody tell me, how temperature of an ideal gas varies on height in homogeneous gravitational field in equilibrium? I mean a gas column perfectly isolated from its environment.
  11. S

    What is the difference between Cp and Cv for an ideal gas?

    I'm just checking that it's okay to use Cv all the time as a heat capacity of an ideal gas, even when the volume's not constant. This is because the average energy per molecule is 3/2*Kb*T from kinetic theory, therefore the average energy per mole is equal to 3RT/2 = CvT etc. I'm currently...
  12. E

    Pressure and temperature changes adiabatically for an ideal gas?

    Question: An ideal gas, which is initially at a pressure of 4.05 atm and a temperature of 355 K is permitted to expand adiabatically to 1.51 times its initial volume. A. Find the final pressure if the gas is monatomic. I was thinking P_i \cdot V_i = P_f \cdot V_f. But, I made no use...
  13. G

    How to Find the Density of an Ideal Gas Around a Planet?

    Hi, I need to find the density \rho(r) of an ideal gas at constant temperature T surrouding a planet of mass M and radius R. The gas is attrated by the planet and is also self-attracting. First, I used the hydrostatic equilibirum equation...
  14. G

    Distribution function of an ideal gas

    Hi, I have the following problem to solve: Consider a planet of radius R and mass M. The plante's atmosphere is an ideal gas of N particles of mass m at temperature T. Find the equilibrium distribution function of the gas accounting for the gas itself and the gravitationnal potential of...
  15. V

    Exploring the Origins of the Ideal Gas Theory and its Disproved Results

    How did the scientists like Boyle and Avagadro did experiments and still got results, which supported the ideal gas theory? It is actually wrong and still how did they get results that volume is inversely proportional to pressure while temperature directly to pressure. I think the only chance of...
  16. A

    Thermodynamics-using ideal gas table

    thermodynamics--using ideal gas table problem says: 6.25 employing the ideal gas model, determine the change in specific entropy between the indicated states, in kJ/kg K. Solve 2 ways: use the appropriate ideal gas table, and a constant specific heat from Table A-20. (a) air, p1 = 100...
  17. G

    Modified equation of state of an ideal gas

    I have this problem, it doesn't seem very complicated but I can't figure out how to do it. A gas obeys to the equation of state P(V-b) = Nk\zeta where k is the Boltzman's constant. The internal energy of the gas is a function of \zeta alone. Show that \zeta=T using a Carnot cycle. Any help...
  18. J

    Momentum and the pressure of an ideal gas. Easy Question.

    My book (Halliday, 6th ed: Section 20-4), uses the momentum of the individual molecules in a gas to derive the pressure of the gas. They imagine the molecules hitting a wall. I'm a little rusty on my memory of conservation of momentum, so this equation is confusing me a bit: (delta)px = (-mvx)...
  19. C

    How Do You Calculate Molar Masses from Diffusion Rates and Density?

    Hi, this is the question I'm having trouble with: A gas mixture is known to contain equal numbers of moles of two gases. The mixture has a density of 1.47g/L at 1.00 atm and 298K. In a diffusion experiment, one of the gases was found to diffuse 1.25 times faster than the other under the...
  20. P

    Do Path-Dependent Processes Affect Thermodynamic Quantities in Ideal Gases?

    An ideal gas changes state from P=32, V=1 to P=1 V=8 via three different paths: first pressure then volume, first volume then pressure, and adiabatically. I need to calculate the change in heat energy, work done by the system, and change in internal energy for all three paths. Will these be...
  21. B

    How Does Temperature Affect Piston Elevation in an Ideal Gas System?

    Hi I got the following physics problem: A cylinder closed by a piston contains 5,00 L of an ideal gass at a pressure of 1,00 amt at a temperature of 20,0 degrees celcius. The piston has a cross-centential area of 0,0100 m^2. The mass of the piston is neglible. The piston is...
  22. S

    How Does Doubling Volume and Increasing Temperature Affect Gas Pressure?

    An Ideal Gas occupies a Volume of 6.00 L at STP. What is its Gauge pressure (in kPa) if the Volume is doubled and the Temperature is increased to 50.0 Degrees Celcius. I don't know where to begine as the question doesn't have a starting Temp, just that it was increased to 50 Degrees Celcius...
  23. S

    Why Does My Ideal Gas Law Calculation Differ from the Textbook?

    hello all. I'm trying to figure out this problem and it's bugging me because it's soooo simple yet i keep getting the wrong answer. here's the problem: If 1.00 mol of carbon dioxide gas at 350 K is confined to a volume of 400 cubic centimeters, find the pressure of the gas using the...
  24. T

    Is the entropy change of the ideal gas equals zero?

    Hi all! I'm a bit puzzled about this question. Is the entropy change of the ideal gas equals zero? And for the second part, is it equal to "Q/T" where Q=200kJ and T=40+273? I'm not sure about how to handle it...please help.
  25. A

    Calculating Work Done by an Ideal Gas in a Three-Step Transformation

    A monatomic ideal gas has pressure p_1 and temperature T_1. It is contained in a cylinder of volume V_1 with a movable piston, so that it can do work on the outside world. Consider the following three-step transformation of the gas: 1. The gas is heated at constant volume until the...
  26. J

    Calculating Pressure and Mass of Ethane Gas in a Flask

    I'm really struggling with this concept and can't seem to get my head around it. I don't know why because it seems simple enough but I can't seem to get the answer :mad:: Question: A flask with a volume 'V', provided with a stopcock, contains ethane gas (C2H6) at a temperature of T_0 and...
  27. C

    Calculating Spacing Using Ideal Gas Law

    Here's the question: For what temperatures are the atoms in an ideal gas at pressure P quantum mechanical? Hint: Use the idea gas law PV = N k_B T to deduce the interatomic spacing. Answer: T < \left( \frac{1}_{k_B} \right) \left( \frac{h^2}_{3m} \right)^{\left(...
  28. I

    Ideal Gas HW: Volume of Bubble Rising to Surface

    Hey, my friend and I have worked on this problem for about 2 hours straight (from our online HW) and can't get the answer right. The help offices and the professor are closed/gone for the weekend. Can anyone please help?! :eek: At 80.0m below the surface of the sea (density = 1.025g/cm3)...
  29. A

    Calculating the Final Temp of an XK8 Cylinder Using the Ideal Gas Law

    A Jaguar XK8 convertible has an eight-cylinder engine. At the beginning of its compression stroke, one of the cylinders contains 499cm^3 of air at atmospheric pressure (1.01×105 Pa and a temperature of 27.0 C. At the end of the stroke, the air has been compressed to a volume of 46.2 cm^3 and the...
  30. P

    Gibbs' Paradox and Ideal Gas Mixture Entropy

    Hi all. About Gibbs' paradox (with the mixture entropy for ideal gases): Is the paradox a Thermodynamic paradox? Because what's bothering me is that in Thermodynamics, the entropy is determined up to a "constant", allegedly, \[ S_0 \] , which in my opinion is dependent of \[ N \] ...
  31. S

    Ideal Gas Equation: Experimental Results & Definition

    Having written about ideal gases, I now have to say to what extent the ideal gas equation of state is an expression of experimental results, and to what extent a definition. My instant reaction is to say it is fully based on experimental results, having been derived from the results of...
  32. S

    Scuba Diving and Ideal Gas Law

    Pressure, volume, and temperature of the air in the diver's lungs when the last underwater breath is taken as p1,V1 , and T1, respectively. Pressure, volume, and temperature of the air in the diver's lungs when the surface is reached to be p2, V2, and , T2 respectively. Salt water has an...
  33. D

    Ideal gas law problems: Pascals vs Atms?

    Hi group, Simple arithmetic problems using PV = nRT or NkT. How do you know when to use pressure units in atmospheres or pascals? For example, in 1 particular problem they give you a pressure in units of Torr, volume in cubic cm and temp in Kelvin and ask for the number of molecules. Couldn't...
  34. D

    Free expansion of an ideal gas

    For the free expansion of an ideal gas into an evacuated chamber, I know that Work=0 and Q=0. Correct? This implies that the change in internal energy dU also equals 0. Since U depends solely on T, this should mean that the final temperature of the chamber is equal to the temperature of the...
  35. B

    Solving Ideal Gas & Spring Problem

    Hi there, I have a problem that I believe I am doing correctly, but my answer proves otherwise. I was hoping someone could take a look and let me know where I'm going wrong. Here's the problem: A gas fills the right portion of a horizontal cylinder whose radius is 5.10cm. The initial...
  36. R

    Calculating Moles and Net Heat in an Ideal Gas Cycle

    Hey, my textbook is not helping at all. Here's the problem followed by what I've done on it so far. A sample of an ideal gas is taken through the cyclic process abca shown in Fig. 20-20; at point a, T = 241 K. graph: http://www.webassign.net/hrw/20_20.gif There are two parts of the...
  37. J

    Find Equation for Ideal Gas in Cube Container

    Hello, I am having some difficulty following the method for finding an equation for an ideal gas. There are a few different forms, but I'm proving 1. For an indiviual particle of a gas in a cube container side length L, it is traveling with a velocity of u1 on the x-axis (its x component of...
  38. C

    Exploring the Differences between Ideal Gas and Van Der Walls Models

    Why does the Van Der Walls equation give a less value for pressure than the Ideal Gas equation does?
  39. A

    How High Does the Piston Rise in an Ideal Gas Problem?

    I think this is a ideal gas/ thermal expansion problem. A cylinder is closed by a piston connected to a spring of constant 2*10^3 N/m. With the spring relaxed, the cylinder is filled with 5 L of gas at a pressure of 1 atm and a temperature of 20 degrees Celsius. a) If the piston has a...
  40. D

    How Quickly Does an Ideal Gas Expand with Temperature Change?

    can anyone give me an equation for the rate that an ideal gas expands in a temperature change. like when a gas goes from 30 degrees to 50 degrees in a baloon. how quickly would it expand?
  41. K

    Solve Ideal Gas Problems: Volume, Translation Energy & More

    There are some problems which have me completely stumped. 1. A balloon has a volume of 10.5dm^3. Its mass is 8.5g and inside is helium at a pressure of 1.05atm. Atmospheric pressure is 1.00atm and both the helium and the outside air is 25.0C (degrees Celcius). Define the tension in the...
  42. H

    Actual Distance Between Atoms of an Ideal Gas

    Hi, I am working on a project in which I need to know the distance between the particles in an ideal gas system. I have tried searching (google) for it but was unable to come with any actual values, just general terms. Can anyone refer me to where I might find this? Thanks
  43. E

    Can someone explain the pressure due to an ideal gas in a container?

    I posted this in the College Level Help forum, but no one responded. I really need some explanation on this, so I'm moving this post from that forum to this. Thanks in advance: Can someone explain why the pressure due to an ideal gas in a container is given by P = \frac{1}{3}\rho<c^2>? (rho...
  44. Z

    How Do You Calculate Final Pressure in Connected Ideal Gas Containers?

    I'm having trouble with this problem. Here's what I know: Since the gas is ideal, we can describe the initial state of the first container with: p_1 V = n_{1i} R T_1 Where p1 is the pressure in the first container, V is the volume of the first container, n1i is the initial number of...
  45. D

    Solve Ideal Gas Problem: Net Work of Cycle

    Okay, I've been working on this for a while: Three-tenths mole of an ideal gas at 400K is expanded isothermally from a pressure of 5x10^5 N/m^2 to 1.5x10^5N/m^2. If the gas is then heated to 500K at constant volume and then is compressed isothermally back to 5x10^5 N/m^2, and then...
  46. D

    Can Compression Turn an Insulator into a Metal?

    Hello, I am in the middle of revising topics for the materials section of myend of year exam. For some reason my department give out past papers but do not give out answers. Any answers to any of the follwing questions would be very helpful. I don't think too much detail is required just a...
  47. M

    How Does the Ideal Gas Law Apply to Changing Conditions in a Gas System?

    Problem1. A cylinder with a movable piston contains gas at a temperature of 42 degrees Celicius, with a volume of 40m^3 and a pressure of 0.233*10^5 Pa. What will be the final temperature of the gas if it is compressed to 0.728 m^3 and its pressure is increaded to 0.609*10^5 Pa? Answer in K...
  48. M

    How Does the Ideal Gas Law Solve Temperature and Volume Changes in Gases?

    Problem1. A cylinder with a movable piston contains gas at a temperature of 42 degrees Celicius, with a volume of 40m^3 and a pressure of 0.233*10^5 Pa. What will be the final temperature of the gas if it is compressed to 0.728 m^3 and its pressure is increaded to 0.609*10^5 Pa? Answer in K...
  49. S

    Ideal gas law constant R conversion

    Hi, not sure if this is the right forum to ask this in, but I was trying to convert the ideal gas law constant R (from PV = nRT) from: 8.31 (Pa * cu. meters) / (mol * Kelvin) to the equivalent: 10.73 (psia * cu. ft) / (lb. * mol * Rankine) Here's the conversion factors I've been using...
  50. X

    Solving Ideal Gas Law: Find Final Volume of Helium

    Given: R=8.31451 J/(K*mol) Two moles of helium gas initially at 187 K and 0.33 atm are compressed isothermally to 0.57 atm. Find the final volume of the gas. Assume the helium to behave as an ideal gas. Answer in units of m^3. I've tried this many many times and i keep getting 5.455...
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