Thermodynamics Definition and 1000 Threads

My inital assumption was to just take T1 = 5600 and T2= 300K, find the maximum efficiency and then divide it by two and three but I don't believe this question to be that simple. I'm confused as to where the 750K fits in as I thought no matter what occurred in between the heat reservoir and heat...

I’m confused on how to calculate molar solubility because I don’t see what’s the difference between that and Ksp.

Hi, as Easter is slowly approaching, I came up with an egg cooking thermodynamics problem that I would like to solve. My formulation of the problem including necessary simplifications is as follows: Let's assume that an egg is a sphere-shaped solid body made of homogenous material (ignoring...

This seems like a simple thermodynamics question but I would like clarification. So the absolute critical temperature is 132.5 K (-221.17 F) and the absolute critical pressure is 3.77Mpa (546.7 psi). I understand that for temperatures above the critical point, a pure substance undergoes an...

I'm new to thermodynamics and after some reading I tried to solve the problem below but I have stuck (I think this problem assumes you know only the first law of thermodynamics) You have a piston resting on some stops inside a container filled with water and you want to find out after heating...

Homework Statement A thermally insulated, rigid vessel is divided into two equal compartments. One contains steam at 100 bar and 400 degrees Celcius, and the other is evacuated. The partition is removed. Calculate the resulting pressure and temperature. (Please let me know if this is the wrong...

Homework Statement A sealed, thermally insulated tank of volume 2 m^3 has a safe working pressure of 4 bar. At 20 degrees Celcius, 10% of the volume is occupied by water, the remainder by water vapour. Calculate how much heat can be added without exceeding the safe working pressure. This...

Homework Statement Three-state system. The nucleus of the nitrogen isotope 14N acts, in some ways, like a spinning, oblate sphere of positive charge. The nucleus has a spin of lft and an equatorial bulge; the latter produces an electric quadrupole moment. Consider such a nucleus to be spatially...

Homework Statement Let x, y and z satisfy the state function ##f(x, y, z) = 0## and let ##w## be a function of only two of these variables. Show the following identities: $$\left(\frac{\partial x}{\partial y}\right )_w \left(\frac{\partial y}{\partial z}\right )_w =\left(\frac{\partial...

Homework Statement A monoatomic ideal gas undergoes a linear process whose equation is given by P/po+V/vo=1. find the volume when the process turns from an exothermic to an endothermic one. P-Pressure V-volume Po= pressure when volume is nearly 0 and Vo is the volume when pressure is...

Homework Statement Homework Equations Ideal gas law The Attempt at a Solution The solution to this problem assumes the pressure inside the balloon is the same as the outside pressure, i.e. atmospheric pressure. Is this a valid assumption? I would guess otherwise.

Homework Statement [/B] Find the equation of state of a solid that has an isobaric expansion coefficient dV/dT = 2cT - bp and an isothermal pressure-volume coefficient dV/dp = -bT (Assume the solid has a volume Vo at zero temperature and pressure. Enter a mathematical equation. Use any variable...

Can an expanding balloon be considered a control volume?

1. Homework Statement What are the values of q, w, ΔU, ΔH for the following constant pressure process for a system containing 0.596 moles of CH3OH ? CH3OH(g, 123.0 ºC, 1.00 atm) ⟶ CH3OH(l, 30.0 ºC, 1.00 atm)Molar heat capacity for CH3OH(g), Cp,m = 44.1 J K−1 mol−1 Molar heat capacity for...

Hi all, I've been for quite a while trying to identify this formula. dV / V = β ΔT - κ Δp where β is the thermal coefficient of volume expansion and κ is the isothermal compressibility. I think it's related to thermodynamics applied to solids and I can understand relations between the...

Homework Statement I have an empty 2-Liter bottle. It contains 3 g of air inside with an initial air pressure of 1105 mb. When I open it (which is an adiabatic process), I release the pressure which is instantaneous. The pressure then becomes standard atmospheric pressure. What is the...

Homework Statement NaCl has a density of 2.16 g/cm3 and a surface energy of 2x10-5 J/cm2. Calculate the surface energy of 1 g of NaCl. Initially the complete 1 g is in the form of a single cube (of mass 1 g) and progressively broken into smaller cubes with sides of 0.1 cm, 0.01 cm, 10 μm, 1 μm...

In thermodynamics, what is the relationship between the terms, "pressure–volume work", "mechanical work", "non-mechanical work", "∫pdV", and "-∫Vdp"?

Hi all, sorry for the condensed title of my post. Any other version of the question I'm trying to ask turned out to be longer than allowed. So, my question is about the wording in some versions of Clausius' statement of the 2nd law of thermodynamics. From time to time I read something like...

##dU = dw + dq ## vs ##dU = dw + dq + µdN## Which equation do we apply to a closed system involving chemical reaction? According to textbooks, the first equation holds for any closed system in the absence of fields and kinetic energy. However, later chapters use the second equation for...

Homework Statement Homework Equations For this problem the correct option is given (c) The Attempt at a Solution If p is the final pressure after the partition is removed then p(V1+V2)=(n1+n2)RTf Tf=p(V1+V2)/[R(n1+n2)] If n1 and n2 moles of the ideal gas is taken in the two compartments...

Homework Statement An inventor claims to have developed a device with the following properties: net work output per cycle = 20,000 J heat output per cycle = 50,000 J high temperature = 450 C low temperature = 160 C Calculate the heat input per cycle. Homework Equations ΔETH = W + Q efficiency...

Hi all, the efficiency ##\eta## of a generic heat engine working between two temperatures is bound from above by the efficiency ##\eta_{\rm C}## of a Carnot machine working between the same temperatures. That is, if the temperatures are the same, a (ideal) Carnot machine is better than any...

<Moderator's note: Moved from a technical forum and thus no template.> My homework says: Gas with a volume of 0.004m^3 is heated with a steady pressure of 1,2atm until the volume turns into 0.006m^3. Calculate the work that the gas produces (Given: 1atm=1,013x10^5 N/m^2). I used the Isobaric...

In my assignment question, the length L and radius r is given and asked to find out how the Temperature of a thin bulb filament which depends on those two parameters. and the answer is r^(1/4)*L^(-1/2). I can't figure out how. Which relation is involved?

Homework Statement I am always confused about how to correctly write the functions U, H, F, G when they're not depending on the usual variables p, V, T, S - same question for Q and W. For example, we have to calculate the temperature variation of a small surface of water when we isentropically...

Homework Statement A dilute gas consisting of N hydrogen atoms in equilibrium at temperature T and pressure P. A fraction of the atoms combine to form diatomic hydrogen. For ##N_{s}## single atoms and ##N_{d}## diatomic molecules, the free energy of the system is $$G =...

Homework Statement Calculate thermal efficiency of R-C cycle with saturated steam as shown in the picture. Steam has 4,5MPa when entering into HP part of the turbine (VT in the picture) and expansion on HP is finished at 0,3MPa. Moisture is then removed in the separator and steam is overheated...

A friend of mine and I have been discussing how to apply the first law of thermodynamics to analyze the quasi static expansion of an ideal gas in a cylinder featuring a piston having both mass and friction (with the cylinder). We have identified two different systems that can be used in the...

I am trying to understand how fluids form particular shapes when put on a solid. In the two figures,what are we taking as a system for the forces? How the resultant of the forces influences the shape of the different fluids?

MODERATOR NOTE: NO TEMPLATE BECAUSE THREAD WAS ORIGINALLY STARTED IN NON-HOMEWORK FORUM I'm struggling with a question on an assignment about thermodynamics: Nitrogen gas, initially at a temperature of 170 K and a pressure of 100 bar, escapes from a thermally isolated tank with a volume of...

Hi! Here's a tricky thermodynamics problem, I hope you can help with it. 1. Homework Statement The boundary between two different materials can be divided into two different kind of phases: bulk phases and surface phases. For example, let's consider a boundary between water and air. We can...

Hi, I have been studying thermodynamics from Herbert Callen's "Thermodynamics : an introduction to the physical theories of equilibrium thermostatics and irreversible thermodynamics" In Chapter 4, Section 4.4, he writes : " all processes occurring between a given initial and a given final state...

I am writing a document on the Joule-Thomson effect. But in my research for it I have come across something that I am not completely clear on. In my document I explained the free expansion of an ideal gas and am trying to transition/segue into the Joule-Thomson effect. However now I am having...

Homework Statement how to know the maximum and minimum temperature for cycle in. Carnot thermal efficiency 60% heat transfer during isothermal expansion 40kj pressure is 5.6bar and volume is 0.3m^3 Homework Equations One kilogram of air as an ideal gas executes a Carnot power cycle having a...

Imagine there is an radiation concentrator (winston cone) surrounded with extremely many layers of foil for radiation insulation, except at the smaller opening. Every part of the setup is initially in thermal equilibrium with the surroundings. The amount of thermal radiation flowing through the...

Homework Statement How to calculate the specific work done. Homework Equations Water vapor initially at 10 bar and 400 °C is contained within a piston-cylinder assembly. The water is cooled at constant volume until its temperature is 150 °C. The water is then condensed isothermally to saturated...

Homework Statement Question If changed isothermal compression process to adiabatic compression process. find the final temperature of process. Homework Equations ## \alpha = \frac{1}{v} (\frac{∂v}{∂T})_{P} ## expansivity ## \beta = -\frac{1}{v} (\frac{∂v}{∂P})_{T} ## compressibility...

Homework Statement 10 kg water temperature 293 K change to ice ( 263 K) at constant pressure. Calculate the entropy change of system Answer is ##-13.8×10^3 J/°C## Homework Equations ##c_p = 4180 J/kg-K## (water) ##c_p = 2090 J/kg-K## (ice) ##l_{water→ice} = 3.34×10^5 J/Kg## ##ΔS = \int...

Homework Statement In a frictionless piston-cylinder system, there are 3 kg of R-134a initially at 280 kPa and 15 °C. Heat is transferred to the system in the amount 120 kJ. What will the final temperature of the refrigerant be (deg C)? Homework Equations Q - W = ΔU (internal energy) Q - Wb...

I'm trying to understand the Seebeck effect in an open circuit of a single material. In other words the system consists of a metal whose ends are kept at different temperature, and we wait long enough for the steady-state to establish. Apparently we can think of the (quasi)electrons in a...

In my heat transfer course, I always had to do analysis of long-wavelength radiation between surfaces first, and find the heat radiated from one of the surface. Then, solar radiation is added to the problem, and suddenly it was said that solar radiation=heat radiated from this surface! Does...

Homework Statement In a certain process, a gas absorbs Q amount of heat and performs kQ amount of work, the molar heat capacity of the gas in terms of R, k and γ(Cp/Cv) is? Homework Equations U=Q+W U=nCvdT Q=CdT The Attempt at a Solution replacing U and Q with the above formulas and W from...

Homework Statement An adiabatic isolated system is formed of three identical balloons (of unknown volume). The balloons are joined by tubes of negligible volume. Each tube has a faucet/tap that is initially closed. The balloons have different quantities of the same ideal gas. After opening...

Homework Statement Derive an expression for the change of temperature of a solid material that is compressed adiabatically and reversible in terms of physical quantities. (The second part of this problem is: The pressure on a block of iron is increased by 1000 atm adiabatically and...

I have become almost sure but have only some small doubts. Are all isothermal process actually ideal gas equation PV=mRT? If all such processes are occur in closed systems, this is so. Because it is isothermal the temperature is constant, R is constant and so is mass for a closed system. So the...

how can we use Cp.dT to evaluate compressor work even when one side (inlet side) is having different pressure than other side (outlet side). Cp should be used for constant pressure!

I'm confused about the mathematics that led to the equation 4.5.9. Specifically, I'm confused about what the variables that describe U are. From the equation I think temperature T(through beta), chemical potential (through alpha), V (through E_s) and N (through... restriction on the...

Homework Statement In all calculations, take R = 8.31 J/m-K. Use the Sackur-Tetrode equation with N replaced by n and K replaced by R to calculate the changes in entropy. Also, assume that these processes are quasi-static so that the ideal gas law and the first law apply at all times. Consider...

If I have a laboratory water bath (circulated for homogeneity in temp) that I will monitor over a period of time (probably 2 scenarios, an hour at most, and then at least 24 hours or longer), how do I quantify the effect of atmospheric pressure in our test lab. What I will do is use an...