Adiabatic expansion Definition and 96 Threads

Homework Statement A 4.00-L sample of a diatomic ideal gas with specific heat ratio 1.40, confined to a cylinder, is carried through a closed cycle. The gas is initially at 1.00 atm and at 300 K. First, its pressure is tripled under constant volume. Then, it expands adiabatically to its...

Hello, I am taking a course on thermodynamics and there was a question on our textbook( "Thermodynamics of Materials" by David V. Ragone) and I can't understand the solution given to me by my prof and I think it is wrong. Homework Statement An evacuated (P=0), insulated tank is surrounded...

http://www.pichem.net/images//reversible-adiabatic//adiabatic-expansion-2.jpg Evidently the adiabatic curve is steeper than the isothermal curve. How can I prove this mathematically using the following facts: P_{1}V_{1} = P_{2}V_{2} for a reversible isothermal process...

Hi, I was looking at the proof for the derivation of the condition satisfied by adiabatic processes. (The proof can be found in many introductory physics textbooks, I am using Principles of Physics HRW 9th ed.) At some point , they say 'For an ideal gas PV=nRT and if P,V T are allowed to...

Homework Statement A real gas obeys Van der Waals‟ equation, which for one mole of gas is (p + A/V2)(V-B) = RT and its internal energy is given by U = CvT - A/V where the molar heat capacity at constant volume, Cv , is independent of the temperature and pressure. Show that the relation...

An ideal gas with g =1.5 is expanded adiabatically. How many times has the gas to be expanded to reduce the rms velocity of molecules 2 times?

Homework Statement see attachment The Attempt at a Solution I'm having trouble where they multiply (101,000 by 1.5 m3)5/3 I get 151,500 Pa*m5 not 199,000 Pa*m5

Homework Statement Argon gas, initially at pressure 100 kPa and temperature 300 K, is allowed to expand adiabatically from 0.01 m3 to 0.029 m3 while doing work on a piston. In this problem you will calculate the contributions to the entropy change, as discussed in Moore, T7.4. a) What is...

Homework Statement Closed system made of a cylinder containing air, compressed by a piston with weights on top of it. The piston is frictionless and its weight can be neglected. The system contains initially 10 kg of air at 27 °C and a pressure of 10 ata. The weights are suddenly halved...

Homework Statement Prove that the work done by an ideal gas with constant heat capacities during a quasi-static adiabatic expansion is equal to W= (PfVf)/(Y-1)[1 - (Pi/Pf)^((Y-1)/Y)] where Y = gamma, which is heat capacity at constant pressure over heat capacity at constant volume...

Homework Statement A sample of 4.00mol of oxygen is originally confined in a 20L vessel at 270K and then undergoes adiabatic expansion against a constant pressure of 600torr until the volume has tripled. Find q, W, dT, dU, dH. Homework Equations U=q+w H=U+PV The Attempt at a Solution q=0...

Hello everyone. I would like to know if I did this correctly. Homework Statement Calculate the heat, internal energy and work of 1 mol of hydrogen, which undergoes a reversible adiabatic expansion from a volume of 5.25 m^3 at 300 K to a volume of 25.5 m^3 The Attempt at a Solution...

Homework Statement One mole of a monatomic ideal gas is taken through the reversible cycle shown below. http://img508.imageshack.us/img508/2595/newbitmapimageqm.png process bc is an adiabatic expansion, with P_b = 10.00 atm and V_b = 10^-3 m^3. Find (a) the energy added to the gas as heat...

for the adiabatic expansion of a gas, why is the temperature drop smaller for a real gas , vs a bigger drop for an ideal gas even though the change in internal energy is greater for a real gas , vs a smaller change for an ideal gas assuming starting temperature, and volume change are the...

for 1 mole of gas, the adiabatic factor gamma is given by Cp,m / Cv,m where the C are molar heat capacities so if now i have 2 moles of gas will my calculation change at all? for example, if i use PVgamma = PVgamma will anything change? it seems weird, it doesn't depend on the...

Homework Statement Suppose the equation of state of a gas is Beta p=rho/(1-b rho) - beta a rho^2 where beta=1/kb T, b is a constant and rho is the molecular density, N/V. The internal energy of this gas is given by U=(5/2)N kb T - N a rho Determine the final internal energy of the gas...

I am having trouble with the very last part of this question. I will write the whole question just to make sure that I haven't screwed up the first part too :) When a certain freon used in refrigeration was expanded adiabatically from an initial pressure of 32 atm and 0degrees C to a final...

Homework Statement 1 mole of a monoatomic gas undergoes reversible expansion from 30 L and 400K to 60 L. The molar heat capacity in this situation is (3/2)R, independent of temperature. Calculate the final pressure and temperature of this process if it is adiabatic. Homework...

How do I calculate the entropy of the surroundings for an adiabatic expansion? I know \DeltaSsur = qrev/T for reversible process and qirrev/T for irreversible process. But q=0 for adiabatic process, so are there any other formulas that I could use to calculate \DeltaSsurr (I know there is a...

Problem: One mole of a diatomic ideal gas, initially having pressure P and volume V, expands so as to have pressure 2P and volume 4V. Determine the entropy change of the gas in the process. Attempt: I thought this would just be R ln(V2/V1)... So, I said (8.314)*ln(4) but it's wrong...

I an working on a problem in the text "Mechanics and Thermodynamics of Propulsion" 2e. The problem states a perfect gas with molecular weight M=20 and a specific heat ratio of Y=1.2 expands adiabatically in steady flow from a pressure of 6MPa, a temperature of 3000K, and a velocity of 200 m/s...

Homework Statement 4 liters of an ideal diatomic gas are compressed in a cilinder. In a closed process, the following steps are taken : 1) Initial state : p_1 = 1 atm = 1.013*10^5 N/m^2 and : T_1 = 300 K 2) Isochoric proces resulting in : p_2 = 3.p_1 3) Adiabatic expansion resulting in...

Homework Statement I'm in a rutt for a tutorial question: The question is basically to show that the work done during a reversible adiabatic expansion of an ideal gas is W = (P1V1 – P2V2)/(1 ‐ γ) ... Y is gamma Homework Equations The Attempt at a Solution I've got so...

Homework Statement Show that when an ideal gas expands adiabatically, the temperature and pressure are related by the differential equation: dT/dP = (2/f+2)(T/P). Homework Equations PV=NkT VT^(f/2) = constant V^(gamma)*P = constant The Attempt at a Solution I started off with the formula...

Homework Statement One mole of an ideal gas at 0 celcius is subjected to changes below, calculate the change in entropy of the gas: i) Gas is expanded reversibly and isothermally to twice its initial volume. DONE - 5.76 J/K ii)A similar expansion to i. is performed reversibly and...

Homework Statement One mole of Ar initially at 325K undergoes an adiabatic expansion against a pressure Pexternal=0 from a Volume of 10.5L to 95.0L. Calculate the final Temperature using Ideal Gas and Van der Waals equations of state. Assume Cv,m=(3/2)R. Homework Equations PV=nRT...

Hi there! I have to determine the work done of a reversible adiabatic expansion. Becauce the system is adiabatic: Q = 0 so \DeltaU = Wrev Becauce both the pressure and the volume changes I can't use W = pex\DeltaV. Homework Statement Cv, Cp, Ti, Tf, Pi, Pf, Vi, Vf are known The Attempt...

Homework Statement One mole of a monatomic ideal gas is taken through the reversible cycle shown below. Process bc is an adiabatic expansion, with Pb = 10.0 atm and Vb = 1.00 x 10-3 m3. Find (a) the energy added to the gas as heat (b) the energy leaving the gas as heat, (c) the net work done...

Homework Statement http://img30.imageshack.us/img30/9954/72990922.jpg The Attempt at a Solution I would say the answer to (a) was no but that would be a guess. Does it have to do with the fact that it's done instantaneously, whereas to achieve anything like an irreversible process...

I'm deriving this formula for the adiabatic expansion of an ideal gas. PV^{\gamma} = Constant_2 there are 3 ways to expand to end up at same internal energy dU. 1. this is the direct adiabatic expansion from T1 to T3 dU_{systA} = -dW_{systA} = -P_{systA} dV where P_{systA} is a function...

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...

Hi, Can anyone tell me what this means? I'm trying to find the adiabatic expansion coefficient in order to use this air compressor calculator. http://www.engineeringtoolbox.com/horsepower-compressed-air-d_1363.html These are the variables I have at the moment... Number of stages-...

Just a question that will hopefully improve my lack of understanding. A thought experiment. I have two cylinders both with frictionless pistons constrained to move in the z direction (against gravity) the same distance in both. So, the intial volume and final volume will be the same for both...

Homework Statement A sample of 2.5 mol O2 (Cp,m = 29.355 J K-1 mol-1) is originally confined in 23 dm3 at 270 K and then undergoes adiabatic expansion against a constant pressure of 600 Torr until the volume has increased by a factor of 3.0. Calculate q, w, ΔU, ΔT, and ΔH. (The final...

(a) For a quasistatic adiabatic process involving an ideal gas the temperature and volume are related by: TV^(a-1) = const . By substituting the ideal gas equation into this expression, derive a similar relationship between pressure and volume for an ideal gas in an quasistatic adiabatic...

Hi, I am going through a book on thermal physics (specifically on a section on the 2nd Law) It talks about an extremely fast adiabatic expression (as a gas in one flask separated by a valve to another flask in vacuum and then the valve is opened). What I fail to understand is that...

Homework Statement A flexible balloon contains 0.375 mol of hydrogen sulfide gas H2S. Initially the balloon of H2S has a volume of 6750 cm^3 and a temperature of 29.0 C. The H2S first expands isobarically until the volume doubles. Then it expands adiabatically until the temperature returns...

Homework Statement Show that when an ideal gas expands adiabatically, the temperature and pressure are related by the differential equation: \frac{dT}{dP} = \frac{2T}{5P} Homework Equations Ideal gas law The Attempt at a Solution PV = nkT T = \frac{PV}{nk} \frac{dT}{dP} =...

Hi Physics forum, I have a pipe which is of length L, inner diameter D. It is packed with CO2 at pressure P (assume it's still a gas with none of this funny supercritical business!) and temperature T. The density of the CO2 is rho and the joule-kelvin coefficient is mu. the pipe is initially...

Homework Statement The molar energy of a monatomic gas which obeys van der Waals' equation is given by E = (3/2)RT - a/V V volume, T temperature, a is a constant. Initially you have T1 at V1, and the gas expands adiabatically in a vacuum so that you have V2. What is T2? Homework...

An ideal gas at 500 K is expanded adiabatically to 6.5 times its original volume. Determine its resulting temperature if the gas is as follows. (a) monatomic (b) diatomic (no vibrations) (c) diatomic (molecules do vibrate) Anything to get me started?

argon enters a turbine at a rate of 800 kg/min, a temp of 800C and a pressure of 1.5MPa. It expands adiabatically as it pushes on the turbine blades and exits at a pressure 300KPa. Calculate its temperature at exit. The equations I am working with are PV^(gamma)=constant and...

Sorry about the repost, but I am frustrated with this problem. An ideal monatomic gas, consisting of 2.47 mol of volume 0.0890 m3, expands adiabatically. The initial and final temperatures are 22.3oC and -64.3oC. What is the final volume of the gas? I've tried solving for P in terms of T...

An ideal monatomic gas, consisting of 2.47 mol of volume 0.0890 m^3, expands adiabatically. The initial and final temperatures are 22.3oC and -64.3oC. What is the final volume of the gas According to a formula in the book, the volume of an ideal monatomic gas' volume expands by 1.52, but I...

Hi, I just need help getting started on a question.. I'm not even sure where to begin: It is desired to ignite a gas at 1000 degrees celcius by compressing it adiabatically to 27 degrees celcius. a) by what ratio must its volume be changed? I'm not really sure how to approach this...

I've been struggling with this problem for an hour or so now, and can't seem to find the right answer. Perhaps someone here can help? I would be very grateful. ;) Two moles of an ideal gas ( = 1.40) expands slowly and adiabatically from a pressure of 5.09 atm and a volume of 12.7 L to a...