Ideal gas Definition and 823 Threads

  1. E

    Why Does the Ideal Gas Law Only Have Two Independent Variables?

    Homework Statement http://ocw.mit.edu/NR/rdonlyres/Physics/8-044Spring-2004/7A20B047-A049-44D6-96D2-75602F179856/0/notes_dfnitns.pdf There it says tht the number of independent variables of a simple fluid is 2 (see the "Complete Specification" section). But the ideal gas law is PV=NkT which...
  2. E

    How Do You Calculate the Probability Density p(E) for an Ideal Gas?

    Homework Statement The following is a probability density distribution for an ideal gas: p(v_x,v_y,v_z) = (2 \pi \sigma ^2)^{-3/2} \exp\left({\frac{v_x^2 +v_y^2+v_z^2}{2 \sigma^2}}\right) E = 0.5 m |\vec{v}|^2 Find p(E). Homework Equations The Attempt at a Solution I want to just plug in...
  3. K

    Calculating Work Done by Ideal Gas: Qualitative Pressure vs Volume

    1. Calculate the work done by 1 mole of ideal gas in expanding adiabatically from V_1 to V_2 (volumes). Make a qualitative figure of pressure changes as a function volume changes p=p(V). I will be very grateful for solving this problem because I spent so much time on it and I still do not...
  4. O

    Partially Emptying a Tank Containing an Ideal Gas

    HI i need help for one of my homework problems. http://img141.imageshack.us/img141/290/sp3220080229004426gf6.gif
  5. C

    The heat capacity of an ideal gas.

    The question states: For an ideal gas ∂U/∂V=0. Show that this implies the heat capacity _{}CV of an ideal gas is independent of volume. I can't wrap my mind around how I could answer this question besides just stating the obvious. The expression for heat capacity is: _{}CV=∂U/∂T (with v...
  6. B

    Is the air in a room an ideal gas?

    Is the air in a room an ideal gas? How do you know this? How does this compare to the density of air at room temperature? thanks
  7. F

    Ideal Gas in Cylinder with Piston (Conceptual)

    You have a cylinder with an ideal gas inside, enclosed by a piston. There is a valve on the side of the cylinder could let gas through if opened. The valve is then opened and some of the gas escapes slowly while maintaining thermal equilibrium. Once it is closed, the piston is a little lower...
  8. E

    Examining the Equilibrium Constant for an Ideal Gas Mixture

    Homework Statement Consider an ideal-gas mixture of atoma A, atoms B and molecules AB, undergoing the reaction AB <---> A+B. If n_A, n_B, and n_{AB} denote their respective concentrations, then show that, in equilibrium \frac{n_{AB}}{n_A n_B} = V \frac{f_{AB}}{f_A f_B} = K(T) (the law...
  9. M

    Work by an ideal gas in a thermodynamic cycle

    1. Homework Statement Two moles of an ideal gas are carried around the thermodynamic cycle shown in Fig. 18-29. The cycle consists of (1) an isothermal expansion A to B at a temperature of 700 K, with the pressure at A given by pA = 9 atm; (2) an isobaric compression B to C at PC = 4 atm...
  10. I

    Ideal Gas Law Application: Finding the Temperature of Air in a Tire

    [SOLVED] Ideal Gas Law Application Homework Statement One Sunday morning a family takes an automobile trip to Grandma's. At the start of the trip, the temperature is 288K (15C), and the gauge pressure in the tires is 32lb/in^2 (psi). (The gauge pressure is the excess over 14.5 psi, the...
  11. W

    How Is Heat Distribution Calculated in a Diatomic Ideal Gas Expansion?

    Homework Statement A diatomic ideal gas expands at constant pressure. What percentage of the heat supplied to the gas is used to increase the internal energy of the gas? what percentage is used to do expansion work? i know Q=CnT, and in the diatomic ideal gas, C_p= \frac{7}{2} R. but i...
  12. A

    How Does Compressing a Syringe Affect an Ideal Gas?

    Homework Statement if you have an ideal gas in a syinge, then you compress the syringe to a point, then that means that Volume has decreased. Consequentally, Pressure must increase to compensate (oin order for PV=nRT to be true) right? I think this is wrong but I am not undersnating why...
  13. E

    Ideal Gas Law Chang ein VolumeProblem

    I am having a little trouble on this problem: Can I treat this as an Isobaric expansion and an Isothermal compression? I think I found the change in Volume like this: \frac{\Delta V}{V_{0}}=\beta\Delta T How do I find the Pressure?
  14. L

    Enviro Chem.- simple ideal gas law calculation.

    Homework Statement 1. Ozone has a maximum concentration of 4.7 x 1012 molecules/ cm3 at an altitude of 20 km. The total pressure at this altitude is 100 torr. Using the ideal gas law, what is the mole fraction of O3 at that altitude? Now express the mole fraction in ppb. Homework...
  15. B

    Ideal gas question(thermal physics)

    Homework Statement estimate the number of air molecules in an average sized room Homework Equations possible equation: N=n*N(a) , N(a) being avogradro number. N being the number of molecules. PV=RTn The Attempt at a Solution So should I guesstimate what n should be and the multiply that by...
  16. I

    Inelastic collision and ideal gas law

    I am not even sure if my question itself is correct. According to ideal gas law, all the collisions for a gas molecules are elastic in nature. Now, suppose a hydrogen atom collides with a neutron (assuming 1-D motion for simplicity), will i consider that collision to be elastic always, or are...
  17. K

    Really simple ideal gas question.

    You know what, I think I might be stupid. I tried this question for 20 minutes already and I am still stucked Homework Statement gas is confined in a tank at pressure of 10 atm and temp of 15C, if half of the gas is withdrawn and temp is raised to 65C, what's the new pressure? Homework...
  18. M

    Ideal Gas Law: Calculating Pressure and Moles of Helium Gas

    ideal gas law...I think... Homework Statement Useful Constants: 1 Torr = 133.32 Pa; R = 8.3145 J/mol·K You have a thin metal sphere of unknown volume that contains helium gas at low pressure. You put the entire metal sphere into a bath of liquid nitrogen, and a pressure gauge on the...
  19. J

    How Many Moles of Air Escape When Heated?

    [SOLVED] Ideal gas law Please help. I don't know what to do. The air temperature and pressure in a laboratory are 23°C and 1.2 atm. A 1.67 L container is open to the air. The container is then sealed and placed in a bath of boiling water. After reaching thermal equilibrium, the container is...
  20. J

    Solving the ideal gas law for volume -&gt; length

    [SOLVED] solving the ideal gas law for volume --&gt; length Consider an ideal gas at 27.0 degrees Celsius and 1.00 atmosphere pressure. Imagine the molecules to be uniformly spaced, with each molecule at the center of a small cube. What is the length L of an edge of each small cube if...
  21. J

    Calculating Ideal Gas Volume with the Ideal Gas Law

    Consider an ideal gas at 27.0 degrees Celsius and 1.00 atmosphere pressure. Imagine the molecules to be uniformly spaced, with each molecule at the center of a small cube. What is the length L of an edge of each small cube if adjacent cubes touch but don't overlap? ______________ I know...
  22. J

    Solving the ideal gas law for moles

    Suppose Gabor, a scuba diver, is at a depth of 15 m. Assume that: 1. The air pressure in his air tract is the same as the net water pressure at this depth. This prevents water from coming in through his nose. 2. The temperature of the air is constant (body temperature). 3. The air acts...
  23. D

    Chemistry - Ideal gas equation question

    A steel gas bottle contains 4500g of oxygen. The pressure of the gas inside the bottle is 6492Pa. If 700g of gas are slowly released from the bottle, what will be the new pressure of the remaining gas? (Assume that the temperature stays constant when the oxygen is released) I'm having trouble...
  24. L

    Calculate Nitrogen Gas Density at 1.7 Atm, 332K

    Homework Statement What is the density of nitrogen gas (molecular mass = 28 u) at a pressure of 1.7 atmospheres and a temperature of 332 K? Homework Equations You must convert pressure from atmospheres to Pascals. I'vedone this using the conversion 1 atmosphere = 1.01*10^5 pascals. I...
  25. J

    Ideal Gas Law: Solve for T2 - Q26

    For this question http://tinyurl.com/3bmkhg Followed is my working P1/T1=P2/T2 T2=(T1/P1)*P2 =(T1)*(P2/P1) =25 * 2 =50 But the answer is D. 323, may I know what is my problem?
  26. C

    Why Does the Ideal Gas Law Fail at the Critical Point of Carbon Tetrachloride?

    [SOLVED] ideal gas law numerically If I calculate the pressure of water vapor at stp (in mmHg), P= 1000*7.502e-3*R*(0+273)*.804/18; where the 7.502e-3 factor converts from Pa to mmHg, 1000 is because my density (.804) is in grams/cm^3, 18 is the molar mass of water, etc etc. and this comes out...
  27. T

    Calculating Gas Temperature Change Using the Ideal Gas Law

    Homework Statement A gas at 293.15 degrees kelvin and atmospheric pressure is compressed to a volume one fifteenth as large as its original volume and absolute pressure of 3000kPa. What is the new temperature of the gas? Homework Equations p1v1/t1=p2v2/t2 The Attempt at a Solution...
  28. O

    Ideal Gas Assumption: No Vibration & Rotation

    Should there also be an assumption for ideal gaes that states: The gas molecules/atoms do not vibrate and rotate I was considering a case of a gas expanding at a dropping pressure such that the value of PV remains a constant. Work is done since there is an increase in volume. If there is...
  29. N

    Ideal Gas Law: Finding dP/dT, dT/dV & dV/dP

    Homework Statement The law for an ideal gas is given by P = n*R*T/V. In our case, n and R are constant, so P = f(V,T). I have found dP/dT, dT/dV and dV/dP. I have to find the result when these three differentials are multiplied with each other. The Attempt at a Solution I get -1 - can...
  30. S

    Which Gas Behaves Most Ideally: N2, CO, or H2?

    Homework Statement In general, which of the following gases would you expect to behave the most ideally? a) N_2 b) CO c) H_2 Homework Equations N/A The Attempt at a Solution Okay, so I know that CO would definitely not behave the most ideally. I tried looking this up on the...
  31. R

    Calculating Volume for 1 kg of O2 at 150,000 Pa and 100K using Ideal Gas Law

    Homework Statement I need to find the volume for 1 kg of diatomic oxygen for a pressure of 150,000 Pa and a temperature of 100K. This is really part of a larger project, and I need to make sure I'm not tripping up on little details. It's that 1 kg of diatomic oxygen that I am a bit unsure...
  32. E

    Virial coefficients of the ideal gas equation.

    Homework Statement Even at low density, real gases don't quite obey the ideal gas law. A systematic way to account for deviations from ideal behavior is the virial expansion. Just working with the first order virial expansion we have: PV=nRT(1 + B(T)/(V/n)) B(T) is a virial coefficient. A...
  33. S

    Understanding Ideal Gas Equation: Tips for Solving Pressure Problems

    Hi, Im having problems with my ideal gas equations. I am able to do the actual equation but when I comes to the answer, I have difficuly understanding. Here is an example. If i want to discover the pressure... V-1000litres n-800moles r-0.08206 t-373kelvin Pressure-? Now the answer...
  34. T

    How Does Adiabatic Expansion Affect Ideal Gas Pressure?

    Homework Statement an ideal gas is allowed to expand adiabatically until its volume increases by 50%. By what factor is the pressured reduced?(gamma=5/3) Homework Equations P1V1^gamma=P2V2^gamma The Attempt at a Solution P1V1^gamma=P2V2^gamma v2=v1+.5V1=3/2V1...
  35. S

    Archived Volume Expansivity of Ideal Gas

    Homework Statement Calculate the volume expansivity, β, for one mole of ideal gas at constant pressure and at room temperature. Homework Equations β=1/V(dV/dT) The Attempt at a Solution Bit stumped on this one, I'm guessing they want it in terms of P as P is not specified. I...
  36. I

    Equation of state for an ideal gas

    Homework Statement What condition must the gas be in for this equation to hold true? Homework Equations The Attempt at a Solution the gas has to be in constant pressure and volume and temperaute
  37. H

    Ideal Gas Law for concave objects

    This is much longer than the normal post, so please bear with me. I was wondering if anyone here knows the complete derivation of Ideal Gas Law (or can recommend a book that describes it clearly and fully), who can tell me whether its conclusions are valid for any shape of gas particle, and...
  38. O

    How Do You Calculate Moles of Water Vapor in Air Using Ideal Gas Law?

    The relative humidity is 55% on a day when the temperature is 30.0°C. Using the graph below, determine the number of moles of water vapor per cubic meter of air. on the graph, Vapor pressure of water is on the y-axis and temperature on the x-axis 30C cordinates with 4200 Pa of water vapor...
  39. H

    Density of water vapour in the air following compression if it were an Ideal Gas

    Density of water vapour in the air involving compression Homework Statement A volume Vi = 23.2 L of air at temperature T = 22 °C is compressed at constant temperature to a volume Vf = 11.0 L. The relative humidity of the air before compression is H = 59.4 %. The saturated vapour pressure of...
  40. R

    Adiabatic compression of an ideal gas

    An ideal gas at a temperature of 17.7°C is compressed adiabatically from an initial volume 70.0 l to a final volume 43.0 l. Find its final temperature (in °C) if CV = 2.50R. so T1V1^g=T2V2^g to find g=cp/cv=(cv+nR)/cv and cv=2.50R g=(2.50R+nR)/2.50R factor out an R...
  41. M

    Problem with ideal gas law and a spring Help please

    Problem with ideal gas law and a spring! Help please! Homework Statement We have a box divided in two parts by a piston without friction, and in one part there are n moles of an ideal gas and a Spring orf constant K and natural longitude L which keeps the piston in equilibrium. According to...
  42. D

    Questions about the ideal gas law - thermodynamics

    im studying building systems engineering technology. yeh i know it's only a technology program at the cegep level but when I'm done with it, I'm going to do software engineering in university. anyways I'm having trouble to understand two problems in the book. if anyone can help me with this, it...
  43. P

    Ideal Gas Law: Low Pressure Application

    Hi every body, We are taught in school that the gas law : pv=nRT can not be applied at high pressure, say a hundred atm. Now I just think of the fact that can we use that equation at very low pressure? Several mTorr for example. Thanks
  44. J

    Solve Ideal Gas Law Problem: V2 and P2 for Ar and N2 mixture at 400 K

    1. A rigid tank contains .5 kmol of Ar and 2kmol of N2 at 250 kPa and 280 K. The mixture is now heated to 400 K. Determine the volume of the tank and the final pressure of the mixture. 2. PV=NRT Can you find the initial volume by using PV=NRT? V=NRT/P V=(2.5)(8.314)(280)/250=23.2...
  45. C

    Ideal gas law + Newton's 2nd law problem

    Homework Statement A cylinder has its lid connected to a spring with k = 2000 N/m. The cylinder is filled with 5.00 L of gas witht he spring relaxed at a pressure of 1.00 atm and a temperature of 20.0C. (a) If the lid has a cross-sectional area of 0.0100 m2 and negligible mass, how high will...
  46. E

    Expansion of ideal gas into a vacuum

    I have a box divided by a partition. On one side I have n mole ideal gas, on the other side there's vacuum. If I remove the partition the ideal gas will expand into the vacuum. Since the box is adiabatic and no work is applied to or by the gas, \Delta U = 0. But what about the work used...
  47. T

    Ideal Gas Law + 1st Law of Thermodynamics

    Hi everyone ^^! I hope you had a great holiday season. I have a homework problem that I'm a little confused on. I will provide my answers/work as usual, and would like it if someone could check my work, or tell me if an explanation is wrong/needs more information. My teacher would like us to be...
  48. L

    Questions on Ideal Gas Homework: Solving for Pressure

    Homework Statement Unknown: Pressure Given: V: 0.002 L n: 0.019 mol R: 8.31 (uh..any units here..?) T: 498 K Homework Equations PV= nRT The Attempt at a Solution For some reason, the units don't cancel out when I attempt to reach the solution when I try to get the Pressure. So what are the...
  49. C

    Ideal Gas Law Helium balloon Problem

    Ideal Gas Law Problem :) Homework Statement A balloon is filled with helium at a pressure of 1.0 x 10^5 Pa. The balloon is at a temperature of 23°C and has a radius of 0.13 m. (a) How many helium atoms are contained in the balloon? (b) Suppose we increase the number of helium atoms in...
  50. M

    PV diagram of a monatomic ideal gas

    Homework Statement Suppose 0.50 mol of a monoatomic ideal gas is changed from state A to state D by one of the processes shown on the PV diagram of the figure below. http://img382.imageshack.us/img382/784/untitledsc4.png (This is my edited version of the image) (a) Find the...
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