What is Pv=nrt: Definition and 47 Discussions

The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations. It was first stated by Benoît Paul Émile Clapeyron in 1834 as a combination of the empirical Boyle's law, Charles's law, Avogadro's law, and Gay-Lussac's law. The ideal gas law is often written in an empirical form:


{\displaystyle PV=nRT}


{\displaystyle P}


{\displaystyle V}


{\displaystyle T}
are the pressure, volume and temperature;


{\displaystyle n}
is the amount of substance; and


{\displaystyle R}
is the ideal gas constant. It is the same for all gases.
It can also be derived from the microscopic kinetic theory, as was achieved (apparently independently) by August Krönig in 1856 and Rudolf Clausius in 1857.

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  1. P

    B Confusion when considering pV=nRT in Two Balloon experiment

    This is the Two-Balloon Experiment: https://en.wikipedia.org/wiki/Two-balloon_experiment#cite_note-MW78-1 The claim on Wikipedia which I am a little confused over is that when 2 balloons (at the 2 red points) are connected via a tube, the smaller balloon at a higher pressure would push air...
  2. lc99

    How to find the Density of Air with PV=nRT?

    Homework Statement Let's say, P = 1.00 atm and T =273K and density of air at STP = 1.29 g/L Homework EquationsThe Attempt at a Solution I'm not too sure... PV = nRT n = PV/RT = P/RT = 1/(0.0821*273) *1.29 g/L ?
  3. R

    Clarification on PV=nRT question.

    A welder using a tank of volume 7.50×10^−2 m^3 fills it with oxygen (with a molar mass of 32.0 g/mol ) at a gauge pressure of 3.00×10^5 Pa and temperature of 36.5 ∘C. The tank has a small leak, and in time some of the oxygen leaks out. On a day when the temperature is 21.0 ∘C, the gauge pressure...
  4. L

    Calculate area of PV diagram. Two isotherms, two isobars

    Homework Statement Everything is in attached file. Given the PV diagram with P2, P1, V2, V1. Homework Equations PV=nRT W=nRT*ln(Vf/Vi) The Attempt at a Solution Attempt in attached file is very organized. I showed 2 of my peers and they are getting the same answer as well. Anybody have any...
  5. R

    Rate of gas leakage through small hole

    Homework Statement Here http://imgur.com/a/4LRM6 2. Homework Equations The equation is given int he questionThe Attempt at a Solution gas will stop flowing when the pressure inside the gas is equal to that of the surroundings. I calculated the final mass of gas inside the cube. Then i...
  6. F

    B Why a dust cloud does not obey pV=nRT?

    Hello all, Another very idiotic question (sorry for the idiotic questions today). From what I learned, a perfect gas obbey pV=nRT because the gas molecules collide against each other in an amazingly elastic way; that is, they may collide a trillion times but will still keep their total kinetic...
  7. J

    Pressure inside pneumatic cylinder

    Hello, I'm having issues with pressure calculations that I'm using for a double acting pneumatic cylinder. In my application, I start the piston near one end of the cylinder with both sides closed, and then move the piston towards the other end. At each point, I update the pressure, volume, and...
  8. K

    Derivation of PV=nRT: Exploring Logic Behind the Ideal Gas Law

    http://quantumfreak.com/derivation-of-pvnrt-the-equation-of-ideal-gas/please check eq.(7) pressure equation is P=F/A which means, in any region over the surface, pressure will be the same. for example, if we assume all the particles have the same mean squared velocity, pressure of one cube will...
  9. wololo

    Chemistry Compare average distance between molecules to size of N2

    Homework Statement Homework Equations Pv=nRt The Attempt at a Solution I already calculated V for a single molecule = 3.99x10^-23 m^3 and the cubic root of this volume gives 3.42x10^-8 m. However, I don't understand what I should do next. What does it mean to compare the value I obtained to...
  10. goonking

    Solving PV=nRT: Finding Volume

    Homework Statement Homework Equations PV = nRTThe Attempt at a Solution n = 5.3 moles R = 8.31 J/(mol K) T = 273 K now, with P, do we use 1 atm or 1.013 x 105 i'll go with the latter, and the answer comes out to be 0.119 liters , does this sound correct?
  11. gauss44

    Home Improvement Project & PV=nRT

    I live in an attic apartment and have been suffering a problem lately. Convection seems to be pushing (nasty kitchen smelling) air up to my apartment from my neighbors who live below me in the same building. This nasty air current primarily seems to be coming from a specific crawl space inside...
  12. A

    U-Tube (Pv=nRT, Pascals) Problem

    Challenge problem 1. Homework Statement A U-tube of uniform cross section contains mercury. The initial temperature of the system is 301K and the barometric pressure is 749 torr. Suppose the left side of the tube is closed at the top and the temperature is raised to a temperature such that...
  13. S

    Pv=nRT Thermodynamics Question

    I managed to get the correct answer, however I don't know if my logic was sound. Homework Statement At ordinary temperature nitrogen tetroxide is partially dissociated (broken up) into nitrogen oxide. Into an evacuated flask of 250 cm^3 volume, 0.86g of liquid N2O4 at 0 C is introduced. When...
  14. R

    Moles of gas helium balloon; buoyancy; PV=nRT

    Homework Statement A helium balloon is used to lift a load of101N. The weight of the envelope of the balloon is46.5N and the volume of the helium when the balloon is fully inflated is31.5m3. The temperature of the air is 0°C and the atmospheric pressure is 1.00 atm. The balloon is inflated with...
  15. B

    Manipulating the PV=nRT Equation for Helium Balloon Volume

    Homework Statement A balloon initially contains 20 grams of helium at a pressure of 1000 torr. After some helium is let out of the balloon the new pressure is 900 torr, and the volume is half of what it was. If the temperature has not changed, how much helium is now in the balloon? Homework...
  16. J

    PV=nRT to PQ=ṁRT where Q - volumetric flow rate?

    Homework Statement Hello, I have really hard time to express the gas law PV=nRT to PQ=ṁRT where Q is volumetric flow rate and ṁ- mass flow rate. Is it possible ? Teacher told me, it is ... Homework EquationsThe Attempt at a Solution
  17. C

    Pressure Volume graph finding total mole of gas

    Homework Statement An ideal monoatomic gas undergoes the following cycle: from 1.) V1 = 1m3, p1=2.5kPa, T1=200k to 2) V2=1m3, p2=7.5kPa then to 3)V3=3m3, p3=2.5kPA, and 4) back to 1). a. Sketch b. How many mole of gas are in the process? c. Give the missing temperatures at positions 2. and 3...
  18. C

    Balloon in Earth's atmosphere

    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...
  19. K

    Derive PV=nRT: Exploring the Ideal Gas Equation

    http://quantumfreak.com/derivation-of-pvnrt-the-equation-of-ideal-gas/ here is the link. so we assume the particle hits two surfaces of the cube, thus pressure is 1/3. combine the equation #11 and #12 we solve kinetic energy equation #12 for mv2. 13...
  20. L

    Will temperature of gas increase or decrease, from the formula PV=nRT?

    Dear all, I would like to ask: Given a control volume (V1), at an initial temperature (T1), the pressure (P1) in the volume (V1) is decreased by sucking out air. The suction hole is then closed to achieve a state of P2 * V2 = n2 * R * T2 . What would happen to the temperature in the control...
  21. skate_nerd

    How would water vapor contamination affect PV=nRT

    Homework Statement Doing a lab here, but were kind of stuck. This lab is meant to experiment the formula PV=nRT, and the set up is a canister of CO^2 with a fixed volume that has a pressure sensor connected to it reading in pascals. We heat up the CO^2 by placing the canister in a beaker of...
  22. S

    Is it possible to write pV=nRT as pV=mRT?

    Hi people. I've been scratching my head for some time now... My teacher of hydrology class keeps posting pV = mRT and I don't know why he is doing that. He's trying to get the density of the air. But I know it should go like this pV =mRT/M... Can someone clarify this for me? :s...
  23. A

    PV=nRT: Volume of Container or Gas? Impact on Temperature?

    i had a question PV=nRT is the V the volume of the container or the gas and if it was the container and i had a balloon and i squeezed it decreasing the volume increasing the pressure will that increase the temperature? thank you
  24. T

    PV=nRT – Why isn’t ‘T’ inversely proportional to ‘V’?

    What am I missing? According to the ideal gas law, as volume increases, temperature increases. However I’m not sure I understand why. I certainly understand the motion of the molecules equals the kinetic energy of the molecules. The faster the molecules bounce about, the more thermal energy the...
  25. C

    Calculating Final Pressure of an Ideal Gas: PV=nRT Help Needed ASAP"

    PV=nRT Need help asap :) An ideal gas has an initial volume of 500 cm3, an initial temperature of 20C, and an initial pressure of 2 atm. What is its nal pressure if the volume is allowed to expand to 1000 cm3 while the temperature increases to 60C? Im trying to work this out i have got...
  26. B

    Exploring Gases: Examining PV=nRT

    Homework Statement I was studying about gases..and a thought struck me: we are taught that gases have no fixed volume. They occupy whole of volume of container in which they're placed. so what are we trying to calculate by the equation PV=nRT . I mean at a particular P T and n, place the gas...
  27. P

    Thermodynamics problem-using PV=nrt

    I have attached the problem statement (untitled) and the solutions (untitled 1). I only have a problem with the second part of the solutions starting at the line "the amount of air that needs to be bled off to restore pressure..." The problem asks what the amount of air that must be bled...
  28. P

    Calculating Mass and Height of Ideal Gas in a Vertical Tank

    Homework Statement A vertical cylindrical tank contains 1.75 of an ideal gas under a pressure of 1.00 at 20.0. The round part of the tank has a radius of 10.0 , and the gas is supporting a piston that can move up and down in the cylinder without friction. What is the mass of this piston? How...
  29. R

    [Chemistry] Trying to find the vapor pressure of water with pv=nRT

    Homework Statement A student found that at 750 torr atmospheric pressure and 0.1 deg C, the corrected volume of the trapped air (in a graduated cylinder filled with water inverted in beaker) was 2.20 mL. Under these conditions, how many moles of trapped air are present? This student then...
  30. N

    Calculating Oxygen Mass in a Portable Cylinder | Physics Homework Help

    Homework Statement In a portable oxygen system, the oxygen (O2) is contained in a cylinder whose volume is 0.0029 m3. A full cylinder has an absolute pressure of 1 107 Pa when the temperature is 290 K. Find the mass of oxygen in the cylinder. Homework Equations pv=nRt The...
  31. P

    Gas Laws Homework: Calculate Mass of Propane Used

    Homework Statement 8. A cylinder 1.00 m tall with an inside diameter of 0.120 m is used to hold propane gas (molar mass: 44.1 g.mol-1) for use in a barbeque. It is initially filled with a gas until the gauge pressure is 1.30 x 107 Pa and the temperature is 22.0⁰C. The temperature of the gas...
  32. L

    Electrical engineering applications requiring the use of gas laws such as PV=NRT etc

    Have you ever used the Ideal Gas Law, Charles' Law, Boyls' Law, or the Combined Gas Law for anything in electrical engineering?
  33. I

    Can Two Points on a PV Curve Represent the Same State in Thermodynamics?

    suppose an Q amount of heat is given to a system initially at v_1 & p_1 vol and pressure. and the system does a equal amt of work on the surroundings so that delU=0. but in doing this work system has expanded to volume v_2 and has a pressure p_2 due to which it is at a different position on the...
  34. fluidistic

    Ideal Gas PV=nRT Cycle: Heat Exchange & Entropy

    Homework Statement Consider an ideal gas whose volume is initially V_0=1cm^3 that is initially at P_0=1 atmosphere. It goes through a cycle a-b-c-a where b-c is at constant temperature. 1)According to the sketch, does the system absorb or release heat? 2)Calculate the heat exchange in a...
  35. C

    Finding dT/t from the pV=nRT Equation

    Homework Statement pV=nRT dV=10cm^3/min dP=-0,3N/cm^2/min n=5mol V=100cm^3 P=2N/cm^2 where d is change. how does tempperature(T) change( dT/t ) compared to time The Attempt at a Solution No idea
  36. F

    Easy Gas Compression question PV=nRT

    Homework Statement Suppose you compress an ideal gas to half its original volume, while also halving its absolute temperature. During this process, the pressure of the gas (a) halves (b) remains constant (c) doubles (d) x4 Homework Equations PV=nRT The Attempt at a Solution...
  37. L

    Basic ideal gas PV=nRT question ( fast )

    A welder using a tank of volume 7.70×10^−2m^3 fills it with oxygen (with a molar mass of 32.0 ) at a gauge pressure of 3.30×10^5 Pa and temperature of 35.0 C. The tank has a small leak, and in time some of the oxygen leaks out. On a day when the temperature is 23.9 C, the gauge pressure of the...
  38. A

    Solve PV=nRT for V on Venus at STP

    Homework Statement The conditions of standard temperature and pressure STP are a temperature of 0.00 C and a pressure of 1.00 atm. For a scientist on Venus, an absolute pressure of 1 Venusian-atmosphere is 92 Earth-atmospheres. Of course she would use the Venusian-atmosphere to define...
  39. J

    Ideal Gas question (PV=nRT)

    The answer key says the answer is 0.3(0.082)(298)/4, using PV = nRT. (0.3 being the number of moles of gas after the reaction.) But according to the coefficients in the reaction, I thought since there are 0.2 moles of SO2 there should also be 0.2 moles of SO3. Is it a typo or am I wrong...
  40. R

    Change in pressure using PV=nRT

    [b]1b]1. Gas is confined in a tank at a pressure of 6.5 atm and a temperature of 9.4◦C. If half of the gas is withdrawn and the temperature is raised to 62.4◦C, what is the new pressure in the tank? Answer in units of atm. [b]2. PV=nRT Ti= 9.4 C + 273= 282.4K Tf= 62.4 C +273=...
  41. R

    Change in pressure using PV=nRT

    [b]1. Gas is confined in a tank at a pressure of 6.5 atm and a temperature of 9.4◦C. If half of the gas is withdrawn and the temperature is raised to 62.4◦C, what is the new pressure in the tank? Answer in units of atm. [b]2. PV=nRT Ti= 9.4 C + 273= 282.4K Tf= 62.4 C +273= 335.4K...
  42. M

    Solving PV=nRT for Solids - How to Determine Temp?

    PV=nRT for solids?? For a perfect gas PV = nRT. This is a very handy little equation that allows determination of temperature given pressure, volume, etc. for gasses, but is there some equivalent equation that relates temperature, pressure and volume for solids? Thanks
  43. S

    Find the Error: Solving PV=nRT for Temperature

    Homework Statement If 1.3 mol of a gas in a container occupies a volume of 9.0 L at a pressure of 1.2 atm, what is the temperature of the gas? Homework Equations PV=nRT The Attempt at a Solution The pressure is in atm so I converted it to Pascals and got 121560 Pa, then I...
  44. V

    How Do You Calculate Work in a Reversible Ideal Gas Cycle?

    Homework Statement One mole of an ideal gas at an inital tempreature of 300K and pressure of 4 atm is carried through the following reversible cycle: a) It expands isothermally until its volume is doubled. b) It is compressed to its original volume at constant temperature. c) It is...
  45. quasar987

    When to apply the ideal gas law PV=nRT

    Is the formula only applicable during quasi-static processes? In other words, is it only true for a gaz at equilibrium?
  46. E

    How Many Balloons Can .1m^3 He @ 150atm Blow Up?

    A tank having a volume of .1 m^3 contains helium gas at 150 atm. How many balloons can the tank blow up if each filled balloon is a sphere .3 m in diameter at an absolute pressure of 1.2 atm. Here is what I have so far: Assuming no gas gas escapes to the atmosphere during transfer, n is...
  47. N

    Real Gas Laws: Exploring Alternatives to PV=nRT

    the ideal gas law PV=nRT only can used on the ideal gas, right? if the we want consider the real gas... what equation should we used??