Thermo Definition and 299 Threads

Homework Statement A hollow aluminum cylinder 20.0 cm deep has an internal capacity of 2.000 L at 20.0°C. It is completely filled with turpentine and then slowly warmed to 80.0°C. (a) How much turpentine overflows? (b) If the cylinder is then cooled back to 20.0°C, how far below the...

Homework Statement This is really just a question that I can't seem to find a good solution for in my book. Basically I'm trying to understand for the first law of thermodynamics how you can derive the equation in term of P1 and P2. I don't understand how to go from PdV to (something)dP. This...

Hydrogen behaves as an ideal gas at temperatures greater than 200 K and at pressures less than 50 atm. Suppose 6.00 mol hydrogen is initially contained in a 100-L vessel at a pressure of 2.00 atm. The average molar heat capacity of hydrogen at constant pressure, cp, is 29.3 J/K/mol in the...

Link between Thermo and Special Rel? Ok, here's the situation: my friends and I were having a sleepover, and right before we slept, we started to talk about physics (lol... what nerds we are...). I began by saying, what if we achieve absolute zero. My friends said, we already achieved absolute...

I have setup the map of my curriculum until I will be graduating, and due to thermodynamics and dynamics only being taught once a year, if I do not take them this upcoming semester I will be in school an additional year. I am wondering if it is possible to take statics, dynamics, and...

I have a simple question that I cannot find a compelling answer for. If I expend (let's say) 100 kJ bending a steel bar into a right angle, where did the energy go? Some will obviously be expended as noise and heat. Will the rest be expended in the plastic deformation of the bar? No useful...

hi...i'm a mechanical student..this semester I'm taking thesis subject and i must find a topic about these two of my fav scope before this week..thermo fluid and in oil and gas industry...and i just want to know which one of these is better for me to concentrate on my thesis? but first, i search...

Hi all, first post so I hope this is ok to go here. It's not a homework question, just something in my book I don't get... I am looking through my thermodynamics textbook (Smith,Van Ness, and Abbot, Intro to Chemical Eng thermodynamics) and they give the eq (6.19): (\partialH/\partialP)T...

Homework Statement Two containers each contain 0.500 moles of N2 initially at 300. K. One container has a fixed volume, and the other container has a movable frictionless piston. If both containers are heated by 1000. J energy, calculate the final temperature of N2 for each container...

This is a statement in my book 'The heat capacity at constant pressure Cp is generally larger than that at constant volume Cv because at constant pressure, a part of heat added to the substance may be used in work of expanding whereas at constant volume all the added heat produces a rise in...

Question: The heat capacity of a bomb calorimeter was determined by burning 6.79 g of methane (energy of combustion = -802 kJ/mol CH4) in the bomb. The temperature changed by 10.8 degrees C. a. What is the heat capacity of the bomb? b. A 12.6 g sample of acetylene, C2H2, produced a...

Homework Statement The average coefficient of volume expansion for carbon tetrachloride is 5.81*10-4 (°C)-1. If a 49.0 gal steel container is filled completely with carbon tetrachloride when the temperature is 10.0°C, how much will spill over when the temperature rises to 27.0°C...

Homework Statement I'm given three temperatures and four pressures for a heat exchanger. I am also given the mass flow rate, which is the same for both the inlets and outlets. There is no heat transfer between the heat exchanger and the surroundings. My task is to find the fourth...

Hi all. I was perusing the grad course options for mechanical engineering at a local school when I noticed a course in statistical thermodynamics. I know the difference btw classical, chemical, and statistical thermodynamics, and that MEs generally learn classical. What are the ME...

Homework Statement 2 moles of an ideal gas, P1 = 10 atm V1 = 5L, are taken reversibly in a clockwise direction around a circular path given by (V-10)^2 + (P-10)^2 = 25. All I have left to solve for is the minimum temperature. Homework Equations PV = nRT The Attempt at a Solution...

Hello PF. I am an undergraduate in physics doing some work in a research lab at school and I need some help with a time-constant calorimetry experiment I am working on. I am attempting to compute the temperature as a function of time of a small sample of copper that I am heating. I am...

A friend has asked a question of me that has me wishing that my days of thermodynamics were not so long in the past. He and some colleagues have been making electrolytic cells for high production of hydrogen and oxygen from water. In demonstrating one to me he posed an experiment that on the...

Homework Statement A semi-conducting thermistor has a resistance that veries with temperature as follows: R(T)=R_0 exp[\frac{B}{T}] What are the SI units of the calibration constants B and R_0 This is just the intro chapter to my second thermodynamics course. Anyway, I'm not sure how to...

Homework Statement Calculate the work done by an external agent in compressing 1.12 mole of oxygen from a volume of 22.4 litre and 1.32 atm pressure to 153 lit at same temperature. Homework Equations related to thermodynamics. The Attempt at a Solution

Homework Statement A certain metal whose thermal expansion coefficient \beta is 5,0 × 10^-5 °C^-1 and whose isothermal compressibility \kappa_T is 1,2 × 10^-6 atm^-1 is at an initial pressure of 1 atm and an initial temperature of 20°C. A thick layer of Invar is thermally insulating the...

I've been trying to solve this for a long time now, I even posted it on this forum a long time ago but no one replied, not even a single response :frown:, I'm not sure if the folks thought I was just trying to make them solve the problem for me or if they actually did not understand it, either...

Hi everybody, i am new to Physics Forums and I have a problem that is confusing me. Any help would be much appreciated. Problem: A perfectly insulated box has vacuum inside of it (it is evacuated entirely) and is sitting with standard atmospheric surroundings (1 bar, 298K). It is then...

you want to boil a pot of water at 110 C diameter of pot = 15cm atmospheric pressure 101 kPa what weight lid should you use? i looked up the steam tables and water boils at 110 C at 143.27 kPa so do i use that pressure or 143.27-101? (gauge pressure) i used gauge and got something...

Homework Statement First law can be written dU = TdS - PdV where the internal energy U may be written in terms of any two of T,P,V,S. I have to show that (DT/DV)s = -(DP/DS)v where D is partial d, and the subscripts s and v mean hold those constant.. Homework Equations The...

Hey guys, I have my final exam in a week for my thermodynamics class. So far this year, things have been sort of roller-coaster-like. I did poorly on my first test because I was caught completely off guard. On my second test, I raised my grade substantially to the point where I was...

Homework Statement derivation of compressibility factor vs. reduced pressure I am supposed to derive the graph by solving equations Homework Equations Van der Waals equation of state compressibility factor, Z = (Pv)/(RT) reduced pressure = P/critical pressure Z = f(Tr, Pr) The...

Homework Statement In a few words, show that \frac{dT_i}{T_i} = 3,73\frac{dr_s}{r_s} Where, r_s = \lim_{P_i\rightarrow 0}\frac{P_s}{P_i} There's a picture below for more details.Homework Equations T_i = \frac{100}{r_s - 1} The Attempt at a Solution So I tried this, T_i = \frac{100}{r_s...

So I wrote my Thermodynamics final today and one of the questions were as follows: A reversible heat engine supplies a reversible heat pump. Both draw off of a temperature reservoir T (can't remember the exact value, but there was one). The heat engine discharges heat into TL, and the heat...

If you were to combine a diesel cycle and a steam cycle (crower cycle) in 1 p-v diagram, what would it look like?

Hello, I am a Security Engineer and deal with system security. I have an interest in Physics and wondered if the second law of thermodynamics applied to system security. My thought is... if you secure a [computer] system as much as possible (this can never be 100%) and leave it. Over time...

ive got this q in my homework calculate the pressure at the centroid and hence the force acting plate. the surface is free liquid is water. ive using a formula l x e = y l being length or depth in this case e being value of water which i found to be 1 x 10 to power of 3 kg/m3 y being the...

Homework Statement An insulated beaker with negligible mass contains liquid water with a mass of 0.325 \rm{kg} and a temperature of 69.9 C. How much ice at a temperature of -15.0 C must be dropped into the water so that the final temperature of the system will be 39.0 C? Take the specific heat...

Homework Statement A person of mass 70.0 kg is sitting in the bathtub. The bathtub is 190.0 cm by 80.0 cm before the person got in, the water was 10.0 cm deep. The water is at a temperature of 37.0 C. Suppose that the water were to cool down spontaneously to form ice at 0.0 C, and that all the...

How do you use the C_ij matrix to find the harmonic frequency (or frequencies) of a diatomic molecule, the OH (hydroxyl) radical? (I have no idea how to set it up for this.) This is from Feynmann's book on Statistical Mechanics...

Homework Statement Air is heated from 300 to 350K at constant volume, Find 1Q2. Homework Equations 1Q2 = m(u2-u1)+1W2 u2-u1 = cv(t2-t1) The Attempt at a Solution The PV diagram of the process is straight up, so the area under the curve is 0, so the work done is zero. Cv is .717...

I need to make thermal analysis for new gear box design to get the answer: do I need additional heat exchanger for that gearbox? I would like to get a help as a source for engineering calculations. Of course, I have already calculated power losses in bearings with TIMKEN software. I don’t have...

Hi this is my first post here. I am attempting to calculate how long it takes for a soda can(355ml) to change from Current room temperature(75F), to say 38F, however the refrigerator or ambient temperature in this case is 35F. I was given a corollary from a friend, but the values I get in...

Homework Statement A thermistor is a solid-state device widely used in a variety of engineering applications. Its primary characteristic is that its electric resistance varies greatly with temperature. Its temperature dependence is given approximately by R = R0e^(B/T), where R is in ohms (Ω)...

A piston / cylinder arrangement with an initial volume of 1 ft^3 contains water at P = 20 psia, T = 320 F. The piston expands against a linear spring until the final temperature and pressure are P = 10 psia, T = 400 F. D)calculate the work and heat transfer in the process, and report in BTU...

Homework Statement If 0.8kg of water at 100 celsius is mixed with 0.8kg of water at 0 celsius, is this process reversible? Homework Equations Entropy: S = mcln(T_2/T_1) The Attempt at a Solution I've already calculated the entropy of the process, which is 81.1 J/K. But how do I...

What is the difference between \DeltaH and \DeltaE in a constant volume process ?

Howdy, Just studying for a test, need to clear something up and I can't find it in any of my books. My question is in regards to N, which to me seems like it is the same as <N> also known as the thermal average occupancy. This quantity represents the thermal average number of the orbitals in...

Homework Statement This is for Statics and mechanics of materials 1... In this project, we were tasked with the re-design of a cheap thermal switch that is to be a component of a low cost product. The switch consists of three metal strips that are bounded on the top and bottom by a rigid...

Homework Statement I have a mixture of saturared water liquid vapor mixture at 200 c, volume = .03 m^3 at 15.54 Bars... the mixture undergoes an isothermal expansion and the volume doubles, what is the new pressure? mtotal = .301 kg Homework Equations this is my prob not sure which...

This is just a conceptual think I have been thinking about. Hopefully I am not just missing something obvious. Imagine we have a large vertically oriented cylinder filled completely with a saturated liquid and the surface contacting the liquid is providing a constant heat flux to the fluid...

this problem is quite long, all I am asking is some for some help by clarifying and hints so i can try to solve this question. Thanks in advance! Consider the combustion of liquid ethanol, C2H5OH(l), to form CO2(g) and H2O(g). Suppose we have 1 mole of ethanol in the presence of 4 moles of O2...

Homework Statement We have a tank of air at 7 atm, 30 L, and 293 Kelvin(20 Celsius), and a flat tire with 1atm, 10 L (Constant), also at 293 K (20 C). The valve is opened quickly and closed quickly when the pressure in the tank reaches 6 atm. Using the Ideal gas assumption and taking the...

Homework Statement I have a system u =Av-2exp(s/R) N moles of this substance initially at T0 and P0 are expanded isentropically until the pressure is halved. What is the final temperature? Homework Equations du = \partialu\partials ds + \partialu\partialv dv du = Tds - Pdv...

Homework Statement Find the three equations of state for a system with the fundamental equation U =(vo\theta/R2)*(S3/NV) For this system, find chemical potential as a function of T,V, and N. Homework Equations \mu= chemical potential \partialU/\partialS = T...

Hello... first post here so take it easy on me. From the Book: "Aquatic Systems Engineering: Devices and How They Function, Selection Installation Operation" by P.R. Escobal In the section about heat loss (section 12.9) the author gives the basic conductivity equation in the form: Q =...