What is Gas law: Definition and 275 Discussions

The gas laws were developed at the end of the 18th century, when scientists began to realize that relationships between pressure, volume and temperature of a sample of gas could be obtained which would hold to approximation for all gases.

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  1. D

    Solve Combined Gas Law Problem: Volume @ STP from -247.7°C & 380 torr

    Can someone explain how to solve the following problem using the Combined Gas Law step by step? What volume will gas occupy if 60.0 mL at -247.7°C and 380 torr pressure are adjusted to STP? Thank you.
  2. F

    Ideal gas law problem in outer space

    Homework Statement In outer space, the density of matter is about one atom per cm^3, mainly hydrogen atoms, and the temperature is about 3.4K. Calculate the average speed of the hydrogen atoms, and the pressure (in atmospheres) M_H = 1.0079au = 1.67 X 10^-27 Kg 1 Hydrogen atom per cm^3...
  3. mishima

    Can gas pressure and density be reduced without changing temperature?

    I'm curious from a lab sort of perspective, how does one keep a gas at a constant temperature yet decrease both pressure and density? Like how could I reduce the pressure of argon gas with the gas kept at room temperature? Put it in a vacuum larger than the space it normally occupies or...
  4. W

    Ideal Gas law and a hot air balloon problem

    My physics problem is as following, Estimate the average temperature of the air inside a hot air balloon. Assume that the total mass of the unfilled balloon and payload is 500kg. what is the mass of the air inside the balloon? we are told to use a radius of 15m Equations needed density = m/V...
  5. E

    Which unit of pressure is used in the ideal gas law?

    The ideal gas law states that pressure (P) is equal to the product of density (N), the ideal gas constant (R) and temperature (T): P = N x R x T I can't figure out which unit the pressure is actually in, although it does seems to work out as the figure I'm supposed to get with a 11706.85°...
  6. T

    Pressure Cooker-Involving Ideal Gas law and Total Pressure

    Homework Statement A cook puts 9.00g of water in a 2.00L pressure cooker and warms it to 500 degree celcius. What is the pressure inside the container.Homework Equations P_{total} = P_{1} + P_{2} +... (eqn1) PV = nRT (eqn2) \frac{P_{1}}{T_{1}} = \frac{P_{2}}{T_{1}} (eqn3) The Attempt at a...
  7. A

    Ideal gas law practical application

    Homework Statement To measure how far below the ocean surface a bird dives to catch a fish, a scientist uses a method originated by Lord Kelvin. He dusts the interiors of plastic tubes with powdered sugar and then seals one end of each tube. He captures the bird at nighttime in its nest and...
  8. L

    Ideal Gas Law Problem - Environmental Physics

    Homework Statement 1. Consider ideal gas in a rigid cylinder of 2 litres, at pressure of 3 Bar. The gas is connected through a thin capillary to a free expanding bag, which contains ideal gas at pressure 1Bar and volume of 1 litre. A valve in the capillary initially prevents the gases to mix...
  9. B

    Volume of Gas At Standard Condition ? Which Gas Law ?

    Homework Statement A Sample of gas 250 mL at 37 C and 730 torr . What volume would gas occupy at standard conditions ? Homework Equations pv = nRT V2 = T2P1V1 ------- T1P2 The Attempt at a Solution Sample Gas V = 250 mL ( 0.250 L ) P = 730 torr ( .960...
  10. V

    Kinetic Energy in relation to the ideal gas law

    I'm trying to fit this together. For monotomic molecules, the avg kinetic energy is 3/2 k_b T for diatomic, it is 5/2 k_b T PV = n_particles * k_b T Why is there no factor of 3/2 or 5/2 in the ideal gas law? How is it factored out?
  11. K

    Can Boyle's Law Determine How Far a Submerged Bottle Must Be Sunk?

    My physics teacher recently assigned this challenge and I have no clue where to begin. I think the ideal gas law might apply but I'm not sure. Any insight? A bottle, full of air at atmospheric pressure, whose volume is 500 cubic centimeters, is sunken mouth downwards below the surface of a...
  12. V

    Ideal gas law - work out temperature and pressure

    A neon tube of volume 1.0 × 10−3m3 holds a sample of 3.0 × 1020 atoms of neon gas in equilibrium. The distribution of speeds of the neon atoms shows a peak at 500 m s−1. The neon may be treated as an ideal gas. (Take the mass of each neon atom to be 20 amu.) What is the Temp & Pressure of the...
  13. L

    Thermodynamics Ideal Gas Law problem (pressure problem)

    Homework Statement If 2.00 m³ of a gas initially at STP is placed under a pressure of 5.00 atm, the temperature of the gas rises to 39.0°C. What is the volume? STP means it's at 0°C and 1 atm of Pressure, correct? V1 = 2.00 m³ V2 = ? T1 = 0°C = 273°K (My main confusion was units: °C...
  14. P

    Ideal Gas Law Problem: Balloon Volume Change @ Different Pressures

    Homework Statement You have a balloon (stretchy) filled with one liter of He at 1 atm and 298 Kalvin. The balloon is suddenly placed into a room at .5 atm and 298 Kalvin. What is the temperature of the gas inside the balloon a little while after this happens? Homework Equations P*V=n*R*T...
  15. L

    Ideal gas law hot air balloon problem

    Homework Statement A hot-air balloon achieves its buoyant lift by heating the air inside the balloon, which makes it less dense than the air outside. Suppose the volume of a balloon is 1900 m3 and the required lift is 2500 N (rough estimate of the weight of the equipment and passenger)...
  16. L

    Problem using the ideal gas law

    Homework Statement In an internal combustion engine, air at atmospheric pressure and a temperature of about 20°C is compressed in the cylinder by a piston to 1/4 of its original volume (compression ratio = 4.0). Estimate the temperature of the compressed air, assuming the pressure reaches 20...
  17. S

    Using Ideal Gas Law to find P, V, or T

    Ok, so I'm doing this homework online and I THINK I'm doing it correctly, but I'm getting incorrect answers. Homework Statement 0.290 mol of argon gas is admitted to an evacuated 40.0 cm^3 container at 60.0 degrees C. The gas then undergoes an isochoric heating to a temperature of 300...
  18. L

    Having trouble using the ideal gas law for this problem.

    Homework Statement A pressure as low as 1 * 10^-8 torr can be achieved using an oil diffusion pump. How many molecules are there in 1 cm^3 of a gas at this pressure if its temperature is 371 K?Homework Equations PV = nRT = NkTThe Attempt at a Solution I converted 1*10^-8 torr to atm and got...
  19. G

    Combined gas law vs. adiabatic relations

    Why is there a difference when calculating pressure temperature and volume using the combined gas law, or when using adiabatic relations? As an idiot I am very confused. Why must I use a very similar equation to calculate the final temperature of an ideal gas but resulting in very different...
  20. T

    How to obtain temperature from a PV vs P diagram using ideal gas law?

    As stated in the question: I have PV(T) [J/kg] vs P [Pa] plotted for 2 different temperatures. I'm to approximate the the temperatures using the lines and the ideal gas law. Note: V is the specific volume. I have no clue how to do this: I know that PV vs P is just as if I had nRT vs P. From...
  21. W

    Can Gas A or B be liquefied and do they have a critical temperature?

    Homework Statement The following equations of state are occasionally used for approximate calculations on gases: (gas A) pVm = RT(1+b/Vm), (gas B) p(Vm -b) = RT. Assuming that there were gases that actually obeyed these equations of state, would it be possible to liquefy either gas A or B...
  22. E

    Find the final temperature? (Ideal Gas Law)

    Homework Statement Find the final temperature? PV relationship -- PV^1.2 = constant P1 = initial pressure = 720 kN/m^2 V1 = initial volume = 0.4 m^3 V2 = final volume = 1.2 m^3 T1 = initial temperature = 225 C I managed to get the final pressure part out of the way but don't know where to...
  23. T

    R is the constant in the ideal gas law.

    Homework Statement i need to derive the ideal gas law Homework Equations this is the equation to end with. PV=NkT The Attempt at a Solution I am not entirely sure where to start with this derivation. I believe Newton laws. where your going to have Fx= Px/t anyone...
  24. C

    Thermodynamics quiz using ideal gas law

    1. Homework Statement T1=300K P1=100kPa V1=1m^3 T1=T2=T3 P2=P3=200kPa V3=0.1m^3 Q: Air initially at 300kpa is contained inside a piston-cylinder device with a volume of 1m^3. The cylinder is equiped with a check valve allowing air to escape when the air pressure reaches 200kPa. An...
  25. S

    Thermodynamics - Ideal Gas Law

    Homework Statement A cylinder contains 2 moles of an ideal monatomic gas that is initially at state A with a volume of 1.0 x 10-2 m3 and a pressure of 4.0 x 105 Pa. The gas is brought isobarically to state B. where the volume is 2.0 x 10-2 m3. The gas is then brought at constant volume...
  26. S

    Ideal Gas Law and dimensional analysis

    Homework Statement The ideal gas law can be recast in terms of the density of a gas. a) Use dimensional analysis to find an expression for the density \rho of a gas in terms of the number of moles n, the volume V, and the molecular weight M in kilograms per mole. b) With the expression...
  27. J

    Calculate Piston Height in Ideal Gas Law Problem | Homework Statement

    Homework Statement A vertical cylinder has a piston of mass "m" on top that is free to move without friction. If there are "n" moles of an ideal gas in the cylinder at absolute temperature "T", what is the height "h" of the piston above the bottom of the cylinder so that it will be in...
  28. J

    Ideal gas law in two dimensions?

    Hi everyone, I know that in P=nRT/v R = 8.314 m3*Pa/mol*k Now, when you are trying to calculate P, if you have volumn in m3 on the bottom, everything cancels out and you are left with Pa. I've just developed a simulator which simulates particle motion over time and calculates...
  29. F

    Truck cylinder, ideal gas law problem

    Homework Statement One cylinder in the diesel engine of a truck has an initial volume of 500 cm^3. Air is admitted to the cylinder at 30 C and a pressure of 1.0 atm. The piston rod then does 450 J of work to rapidly compress the air. What is its final temperature? What is its final volume...
  30. O

    Ideal Gas Mixture Composition Calculation

    Homework Statement A rigid cylinder of 1000cm cubed contains 4.168grams of an ideal gas mixture. The gas mixture consists of methane and ethane at a temperature of 100C and a pressure of 500kPa a) Estimate the average molar mass of the mixure b) Calculate the composition of the mixture on a...
  31. A

    GAS LAW and other PRE LAB HELP

    #1-Use the Ideal Gas Law to calculate the number of moles of gas at 1.00atm in a cell 10.0cm long having a cross sectional area of 1.00cm^2 at 298K. (1ml=1cm^3) #2-Lets say you start with 6.0 x 10^2 mL of 1.0 x 10^-4 M NaOH solution containing phenolphthalein indicator. The equation is...
  32. C

    Ideal Gas Law- finding gas density

    Homework Statement What is the density of radon gas at 0 degrees C and 1 atmosphere? Homework Equations PV= nRT 0 C = 273 K density = mass/volume g/m^3 The Attempt at a Solution I want density = g/m^3 Below are the units of PV = nRT. I thought that breaking it down...
  33. I

    Solve Gas Law Problem: Find Average Kinetic Energies of CH4 & N2

    Gas Law problem... please help Calculate the average kinetic energies of the CH4 and N2 molecules at 294 K and 574 K. I've tried every possible way I could think of. I can't get the right answer. I don't know what equation to use anymore, I've done it all and nothing works. I got all...
  34. S

    Andrew mason ideal gas law and adiabatic expansion problem

    Q1. ADIABATIC FREE EXPANSION(unrestricted and free) in vacuum gas a volume of gas is released expected expansion proceeds withouut change in internal energy therefore temperature is contant (joule's law) . there is no pressure acting on this system threfore no work is done...
  35. F

    Question concerning Ideal Gas Law correction to a teacher & tactons

    Whoops, I meant to say tact. Hehe, maybe tactons are the gauge bosons for the tact force. My Chemistry teacher, who has a Ph.D in Biology., is teaching us that one can use the Celsius temperature scale for the Ideal Gas Law using (approximate) R = 0.0821 \frac{atm * L}{mol * K} . Where R is...
  36. G

    Ideal Gas Law: Solve 1.0x10-6 mmHg @ 40°C

    Homework Statement Current vacuum technology can achieve a pressure of 1.0x10-6 mm of Hg. At this pressure, and at a temperature of 40.0 C, how many molecules are in 1.00cm3 ? [b]2. Homework Equations [/b pv=nrt The Attempt at a Solutioni solved it using the ideal gas equation and...
  37. G

    Ideal Gas Law and a helium tank

    Homework Statement Helium in a steel tank is at 250kPa, 300K with a volume of .1m^3. It is used to fill a balloon. When the pressure drops to 150kPa, the flow of helium stops by itself. If all the helium is still at 300k, how big balloon is produced? Homework Equations I used the ideal...
  38. M

    AP Question involving Ideal Gas Law - Thermal Physics - Pressure

    [SOLVED]AP Question involving Ideal Gas Law - Thermal Physics - Pressure I am having some trouble with an old ap problem(PART C ONLY), see below: Homework Statement 1996 AP PHYSICS B Free Response Question: The inside of the cylindrical can has a cross sectional area of 0.005 m^3 and...
  39. P

    An approximation of the ideal gas law for real gases

    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, PV=nRT(1+B(T)/(V/n) + C(T)/(V/n)^2+...) where functions B(T), C(T) and so on are called the virial...
  40. P

    Ideal gas law problem concerning the exponetial atmosphere: part 4

    [b]1. Homework Statement [/b Estimate the pressure , in atmospheres, at the following locations:Odgen Utah(1430 m above seas level);Leadville colorado(3090 m) Mt. Whithney (4420 m) and various other cities above sea level. (assume that the pressure at sea level is 1 atm.)Homework Equations...
  41. S

    How High Can Temperature Go with 10^4 Joules in a Monoatomic Gas Cylinder?

    Homework Statement This is Pathria (2nd Ed) 1.6 and it seemed simple enough but the magnitude of the answer seems unbelievably large: A cylindrical vessel 1 m long and .1 m in diameter is filled with a monoatomic gas at P = 1 atm and T = 300 K. The gas is heated by an electrical discharge...
  42. P

    Ideal gas law problem : part 3

    Homework Statement Assuming that the temperature of the atmosphere is independent of height, solve the barometric equation to obtain the pressure as a function of height: P(z)=P(0)exp(-mgz/kT) Show that the density obeys a similar equation. Homework Equations dP/dz=-mgP/kT...
  43. P

    How do I solve for dP/dz in the ideal gas law using mass and density?

    Homework Statement Calculate the mass of a mole of dry air, which is mixture of N2(78 percent by volume, O2 (21 percent) and argon (1 percent). Use the ideal gas law to write the density of air in terms of pressure, temperature , and the average mass of the air molecules. Show , then...
  44. P

    Ideal gas law concerning the exponential atmosphere

    Homework Statement Consider a horizontal slab of air whose thickness(height) is dz. If this slab is at rest, the pressure holding it up from below must balance both the pressure from above and the weight of the slab. Use this fact to find an expression for Dp/dz, the variation of pressure...
  45. P

    Which room contains the greater mass of air?

    Homework Statement Rooms A and B are the same size and are connected by an open door. Room A however, is warmer(perhaps because its windows face the sun). Which room containks the grater mass of air? explain carefully. Homework Equations PV=nRT, PV=NkT, N=Na*n The Attempt at a...
  46. M

    Solving Gas Law Problems: Partial Pressure & Relative Diffusion Rates

    heres a partial pressure one: 1. A mixture of gases containing equal weights of carbon dioxide, CO, and ammonia exerts an overall pressure of 450 torr. What pressure is exerted by each gas individually? my last question is: 2. The relative rate of diffusion between two gases is 1.89. If the...
  47. G

    How Does the Mole/Mass Ratio Affect Pressure Calculations in Turbine Engines?

    What is the mole/ Mass ratio for ambient air at a given Temp/ Humidity? I am trying to get a very rough calculation of a pressure increase in a turbine engine with a given increase in temperature. In the ideal gas law alternative of PV=m/M(RT), The only part of the equation I am having...
  48. G

    Ideal Gas Law and a gas bubble

    Homework Statement A gas bubble with a volume of 0.10 cm^3 is formed at the bottom of a 10.0 cm deep container of mercury. If the temperature is 27C at the bottom of the container and 37C at the top of the container, what is the volume of the bubble just beneath the surface of the mercury...
  49. H

    Formula One Relating to the Combined Gas Law

    I'm doing an investigation, for my GCSE coursework, on how the combined gas law can be applied to formula one racing. For example: the tyres. Can anyone give me any ideas on what to put into my investigation. Thanks in advance.
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