Ideal gas Definition and 823 Threads

Homework Statement Suppose that you measured the product pV of 1 mol of a dilute gas and found that pV = 22.98 L atm at 0°C and 31.18 L atm at 100°C. Assume that the perfect gas law is valid, with T = t(°C) + a, and that the value of R is not known. Determine R and a from the...

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...

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...

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...

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...

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...

I am trying to deduce the expression for pressure of perfect gas when the momentum distribution n(p) is given. Here is how I did. First we assume a box with side length L_x, L_y, L_z, when a particle , say moving a long x direction, collide with one side of the wall, the total change of...

I was studying the Ideal gas properties of air. Among other properties like h, P_r, U, V_r I also found an S^o. What is this entropy like thing ?

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...

Homework Statement If you increase the temperature of an ideal gas, then a. the average distance a molecule travels between collisions must increase b. the pressure must increase c. the speed of its molecules must increase d. the average time between collisions of its molecule must...

The mass of a hot-air balloon and its occupants is 289 kg (excluding the hot air inside the balloon). The air outside the balloon has a pressure of 1.01 x 105 Pa and a density of 1.29 kg/m3. To lift off, the air inside the balloon is heated. The volume of the heated balloon is 890 m3. The...

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...

The derivation of the ideal gas equation employs two assumptions that are invalid for real gas molecules. First, the equation assumes that the molecules of the gas have no volume, which is not true for real molecules. Since the molecules will have some physical volume, the volume that the gas...

Homework Statement A diver observes a bubble of air rising from the bottom of a lake (where the absolute pressure is 3.50 atm to the surface (where the pressure is 1.00 atm). The temperature at the bottom is 4.0 C, and the temperature at the surface is 23.0 C}. What is the ratio of the...

Hi all, I was brushing up on statistical ensembles, and I found something apparently weird in microcanonical treatment of the ideal "classical" gas. I'm mainly following K. Huang's Statistical Mechanics. So there's a first approach to the problem in which the MC entropy is evaluated via an...

Homework Statement 1) Consider one-mole of gas in a heat engine undergoing the Otto Cycle a) The gas absorbs heat, at constant volume between 120'C and 300'C b) The gas expands adiabatically from V1 to V2 = 5V1 c) The gas cools, at constant volume to Td at point D where the pressure is 1At d)...

Homework Statement An empty room in a house near the Atlantic coast has a volume of 45m3. What is the kinetic energy of all of the gas molecules in the room on a 30C summer day? Homework Equations pv = nrt The Attempt at a Solution I realize that this is an ideal gas law problem, but I...

I'm trying to determine the internal volume of a container using the ideal gas law principle. 1. A container of known volume is pressurized with air to some known value relative to ambient. 2. The container of unknown volume is vented to ambient. 3. Temperature is constant for all air...

Homework Statement One mole of an ideal gas is a temperature 300K adn at 1.00 atm pressure. a) find the volume. b) Estimate the average spacing between the particles of the gas. Homework Equations For the first part I used PV=nRT and solved for V to determine the volume which I found...

Homework Statement An ideal gas expands from the state (p_1, V_1 ) to the state (p_2, V_2 ), where p_2 = 2p_1 and V_2 = 2V_1. The expansion proceeds along the straight diagonal path AB shown in the figure. Find an expression for the work done by the gas during this process. Express your...

Homework Statement In a period of 1 s, 5 x 10^23 nitrogen molecules strike a wall with an area of 8 cm^2. Assume the molecules move with a speed of 300 m/s and strike the wall head-on in elastic collisions. What is the pressure exerted on the wall? (The mass of one N2 molecule is 4.68 x...

Homework Statement Show that:- a) the expansivity \beta = \frac{1}{T} b) the isothermal compressibilty \kappa = \frac{1}{P} Homework Equations P\upsilon = RT where \upsilon = molar volume The Attempt at a Solution A big mess!

If one considers an ideal gas, what does the mean time between collissions of the molecules depend upon? molecular size? number per unit volume? temperature of the gas? I'm thinking so far, it must def depend on number density. It would usually depend on molecular size (but I thought an ideal...

A sealed balloon is filled with 1.00 L of He gas at 23 deg C and 1.00 atm. The balloon rises to a point in the atmosphere where the pressure is 220 torr and the temperature is -31 deg C. What is the final volume of the balloon after it reaches an altitude where the pressure is 220 torr? If...

Homework Statement hi, can anyone help me with this problem? a motorist equips his automobile tire with a relief type valve so that the pressure inside the tire never exceeds 240 KPA(gage). He starts a trip with a pressure of 200 KPA(gage) and a temp. 23'C in the tires.During the long...

Homework Statement Three moles of ideal gas are in a rigid cubical box with sides of length 0.380 m. Homework Equations What is the force that the gas exerts on each of the six sides of the box when the gas temperature is 24.0 C? What is the force when the temperature of the gas is...

Homework Statement The pressure p , volume V, number of moles n, and Kelvin temperature K of an ideal gas are related by the equation pv=nRT , where R is a constant. Prove that the coefficient of volume expansion for an ideal gas is equal to the reciprocal of the Kelvin temperature if the...

Homework Statement The cylinder and piston are made of a thermal insulator. An atom of a gas collides with the piston at an angle and bounces off at an angle. State with a reason whether momentum of the atom is conserved in this collision. Homework Equations The Attempt at a...

The “ideal gas” law The well-known, encyclopaedic experimental data (about gas compressability factor) show the general trend: the more rarefied gas the more accurate “ideal gas” law, or the same in other terms: the higher vacuum the more accurate “ideal gas” law. 1) Are another...

Homework Statement A gas sample enclosed in a rigid metal container at room temperature (20 C) has an absolute pressure p_1. The container is immersed in hot water until it warms to 40 C. What is the new absolute pressure p_2? Express your answer in terms of p_1 Homework Equations PV = nRT...

guys, I'm having difficulty in solving this problem. Two vessels, one having 3 times volume of the other, are connected through narrow tube of negligible volume. The initial temperature is 290K. The small vessel is then cooled down to 250K while the large vessel is heated up to 400K. What is...

Homework Statement Diagram here: http://img99.imageshack.us/img99/7189/systemgk9.jpg Two bulbs, A of volume 100cm3 and B of volume 50cm3 , are connected to a three way tap T which enables them to be filled with gas or evacuated. The volume of the tubes may be neglected. Initially bulb A is...

Homework Statement A cylinder with a frictionless piston is placed horizontally in an atmosphere pressure 1 * 105 N/m2. A gas in the cylinder is initially at a temperature of 300K with a volume of 6.0 * 10-3 m3. Then the gas is heated slowly to 400K. How much work is done by the gas in the...

Homework Statement A classical system of N distinguishable, non-interacting particles of mass m is placed in a 3D harmonic potential, U(r) = c \frac{x^2 + y^2 + z^2}{2 V^{2/3}} where V is a volume and c is a constant with units of energy. (a) Find the partition function and the...

Hi, So let's take the standard example of a gas in a container with a piston at the top. Charles' Law states that at constant pressure, an increase in temperature (kinetic energy of gas molecules) will increase the volume. This makes sense both conceptually and mathematically (per PV = nRT)...

Homework Statement On a warm day 90F, the air in aballon occupies a volume of .25m3 and exerts a pressure of 20 lb/in2. If the baloon is cooled to 30F in a refrigerator, the pressure drops to 14.2lb/in2. What is the volume of the balloon Homework Equations...

Homework Statement one mole of a monatomic gas expands from V_i = V_0 to V_f = 3V_0 according to the relationship: p = P_0[1 - 0.9sin( (pi(V - V_0))/4V_0 )] a) compute the work done by the gas as it expands from V_i = V_0 to V_f = 3V_0 b) compute the net heat flow during this expansion c)...

Homework Statement two moles of an ideal gas is initially at P = 2*20^5 Pa expands adiabaticaly to four times its original volume. it is then compressed at constant pressure to its original volume. what is the change in entropy of the gas Cp = 20.78 joules/mole-deg Cv = 12.47...

Homework Statement an ideal gas operates in a carnot cycle so that it produces a net positive work of 400 joules per cycle. the maximum temperature during the cycle is 300 deg celsius and the heat lost to a low temperature bath is 600 joules per cycle. a) what must be the temperature of the...

Homework Statement An ideal gas expands isothermally, performing 3.40x10^3 J of work in the process. a) The change in internal energy of the gas b) The heat absorbed during this expansion Homework Equations \DeltaU=Q-W The Attempt at a Solution a) Since it's isothermally...

[SOLVED] Monatomic Ideal Gas volume expansion Homework Statement A monatomic ideal gas expands slowly to twice its original volume, doing 260 Joules of work in the process. (a) Find the heat added to the gas if the process is isobaric. (b) Find the change in internal energy of...

[SOLVED] Work Done and final temperature of 5 mols of Ideal Gas Homework Statement Five moles of an ideal monatomic gas with an initial temperature of 129 degrees Celsius expand and, in the process, absorb an amount of heat equal to 1160 Joules and do an amount of work equal to 2020 Joules...

[SOLVED] Internal Energy of an ideal gas Homework Statement The temperature of 0.158 mol of an ideal gas is held constant at 67.0 degrees Celsius while its volume is reduced to a fraction of 20.0 % of its initial volume. The initial pressure of the gas is 1.19 atm. What is the change in...

Homework Statement When the volume of a gas is 2.81 L, the pressure is 740 Torr and the temperature is 20oC, how many moles of gas is there? Homework Equations PV=nRT The Attempt at a Solution 740 Torr = 740*133.3 = 98.6*10^3 Pa Temperature in Kelvin: 293 K n = PV/RT =...

Homework Statement An ideal gas of N molecules of mass m is contained in a cylinder of length L and radius R. The cylindrical container is rotating about its axis at an angular velocity \omega, and is at equilibrium with temperature T. Write down the energy for single particle states, and the...

A bubble, located 0.200 m beneath the surface in a glass of beer, rises to the top. The air pressure at the top is 1.01 X 10^5 Pa. Assume that the density of beer is the same as that of fresh water. If the temperature and number of moles of CO2 remain constant as the bubble rises, find the ratio...

Oxygen for hospital patients is kept in special tanks, where the oxgen has a pressure of 65.0 atm and a temp. of 288 K. The tanks are stored in a separate room, and the oxygen is pumped to the patient's room, where it is administered at a pressure of 1.00 atm and a temp. of 297 K. What volume...

Homework Statement A system is contained within the walls of a box and a movable piston. An object weighing W is placed on the piston. If you regard the gas and the piston as an isolated system, use the microcanonical ensemble to deduce the equation of state for p (pressure). Take a look at...

I've been looking at Charles law, Boyles law, the Pressure law, and the Ideal gas law, PV=nRT. I want to know, what limitations are there to the gas law? Basically, why aren't real gasses ideal, when isn't it possible to use the ideal gas law, and in such a case, what else do you have to use...

[SOLVED] Gas laws Homework Statement A balloon containing 2000m^3 of helium gas at 1.00atm and a temperature of 15.0 C rises from ground level to an altitude at which the atmospheric pressure is only 0.900atm. Assume the helium behaves like an ideal gas and the balloon's ascent is too rapid...