Thermodynamics Definition and 1000 Threads

Thermodynamics is stated in different ways. E.g. In isolated systems entropy never decreases Heat never spontaneously pass from colder to warmer body Total energy quality decreases in all processes. Energy disperses But what is it exactly? What is the correct description of the 2nd law of...

Homework Statement The temperature of n = 19 mol of argon gas is increased from T1 = 21 oC by Q = 4.4 kJ heat transfer, while the gas pressure is kept constant. What is the new gas temperature in Celsius degrees? Homework Equations and as its a monoatomic gas I think this means that the...

Homework Statement You're in Paris, working on your first novel and short on cash. The owner of the cabaret downstairs has offered to take care of your rent if you'll help her design a climate control system for the place. It gets too hot and damp in the summer, and too cold and dry in the...

Hi guys, I am currently working on my master thesis. I am supposed to make a dynamic model for a gas system and have some trouble setting up the energy balance. I am a noob when it comes to uploading pictures, so I don't have a figure for this, but let's consider a general control volume (CV)...

Homework Statement A certain mass of water in a copper pot is heated over a stove that releases joules of heat to heat the water. Later the same mass of water in an aluminum pot is heated over another stove that releases the same amount of heat in order to heat the water. Then the water in...

Homework Statement A container of 1.5 Kg of gas is at a temperature and pressure of 293 K and 1 bar respectively. The gas is adiabatically compressed until its temperature and pressure are 450 K, 4.49 bars. Adiabatic processes are processes with no heat transfer. The properties of this...

Homework Statement 1. You are cooking a meal in your kitchen and have just put a pot of frozen soup on the stove to defrost. You turn on the burner and, when you ignite the gaseous fuel (methane or propane), there is a dramatic increase in the gas's thermal energy. Where did that thermal...

Homework Statement A beam of molecular oxygen containing 1010 molecules/cm3 and average speed of 500 m/s strikes (elastic collision) a plate at an angle of 30º with the normal direction. Calculate the exerted pressure on the plate. Homework Equations P = Impluse x Flux The Attempt at a...

Homework Statement Estimate the pressure increase required to impart 1 J of mechanical work in reversibly compressing 1 mol of silver at room temperature. What pressure rise would be required to impart 1 J of work to 1 mol of alumina at room temperature? For alumina take the molar volume to be...

Homework Statement Suppose that heat leaks into your kitchen refrigerator at an average rate of 300W. Assuming ideal operation, how much power must it draw from the wall. Homework Equations \eta = \dfrac{T_C}{T_H - T_C} W= \dfrac{Q}{COP} The Attempt at a Solution A typical refrigerator...

Homework Statement Suppose you have a mole of water at 25##^{\circ}## at atmospheric pressure. You then raise its temperature to 30##^{\circ}##. Determine the change in Gibbs free energy. To compensate for the change, once can raise the pressure on water, how much pressure you need to increase...

"HOMEWORK" PROBLEM ORIGINALLY POSTED IN WRONG FORUM, SO NO TEMPLATE a rigid vessel of volume 1m^3 contains steam at 25 bar and 450c the vessel is cooled until the steam is just dry saturated calculate the mass in the vessel the final pressure and the heat rejected during the process? i know i...

In my Thermodynamics course, we recently learned about the saturation pressure and saturation temperature of different substances -mainly water. As you know, the saturation temperature at which a substance begins to boil is specific to a fixed saturation pressure. Water only boils at 100...

Homework Statement Find the expression for c_p - c_v for a van-der-waals gas, with the equation of state \Bigg{(}p+\dfrac{a}{V^2}\Bigg{)}(V-b)=RT Homework EquationsThe Attempt at a Solution Basically I've proved c_p - c_v = \Bigg{[} p + \Bigg{(}\dfrac{\partial E}{\partial V}\Bigg{)}_T...

Homework Statement Hi all, I'm having quite a big problem trying to understand the concept of enthalpy and free energy. I feel that a good way to sort this out is to write out what I understand about these things and have people correct me. Thanks in advance for any assistance. I'm learning...

Homework Statement [/B] A four-stroke petrol engine with a compression ratio of 9 has a total swept volume of 2.71 litres distributed over 4 cylinders. Assume the corresponding ideal thermodynamic cycle and the following conditions to calculate the maximum amount of fuel which can be safely...

Homework Statement Can you please show how to solve this question (I am not asking it for homework. I am asking because it would help me understand better). Determine the entropy change in sys, surr, uni, when a sample of helium has of mass M grams at 298K and 1 bar doubles its volume in...

Homework Statement Homework Equations P=F*V, dU=Q-W?, W=m(h1-h2) The Attempt at a Solution I have the initial conditions and final conditions written out. For W=m(h1-h2), I have W=9.48(h1-h2). I am having problems with the h values, which can be found in the steam tables.

Homework Statement [/B] Phospine exist in three forms. known as the \alpha, \beta and \gamma forms. The \alpha and \beta forms are in equilibrium with each other at 49.43 \, K, and the \alpha and \gamma forms are in equilibrium at 30.29 \, K. Obtain the molar heat of transformation for the...

Homework Statement Homework EquationsThe Attempt at a Solution U is internal energy, but what is u? if its internal energy at a specific state, then why its multiplied by mass? does not makes sense to me...

The third law of quantum mechanics states that a system at absolute zero temperature has zero entropy. Entropy can be conceived as an expression of the number of possible microstates that can produce an identical macrostate. At zero entropy, there should be exactly *one* microstate configuration...

Homework Statement Two vessels A and B each contain N molecules of the same perfect monatomic gas. Initially, the two vessels are thermally isolated from each other, with the two gases at the same pressure P and at temperatures T_A and T_B. The two vessels are now brought into thermal contact...

Homework Statement Use the IPCC estimate of anthropogenic SO2 emissions of 55 ⋅ 109 kg/year and natural SO2 emissions of 15 ⋅ 109 kg/year to estimate the residence time of SO2 in the atmosphere. Is the residence time consistent with SO2 emissions being able to travel from Ohio to Maine as...

Hey Guys! I need some help for solving question 2 of this example as my HSC exam is in 5 days and I want to be able to solve this question if I receive it on the paper. Question: Graph: Answer for Q1 (Just the formula) : Work I have done towards this question: I have realized that from...

Homework Statement Question: https://imgur.com/a/8rUw1 Graph: https://imgur.com/a/Z1oBO Homework Equations Answer for Q1 (Just the formula) : https://imgur.com/a/uesqN The Attempt at a Solution I have realized that from 1-2, there is an increase in pressure, decrease in volume and increase...

Homework Statement Homework Equations when constant pressure, h=w+u and so H=W+U=Q when U=E. However, in this question, when constant pressure, Q(=12750kJ)=W+U =/= H[=m(h2-h1)]. The Attempt at a Solution [/B] here's my calculation of enthalpy...

In a heat engine thermal energy is converted into mechanic energy. In a heat pump or refrigeration cycle - fluid is being circulated between hot and cold wells. But how can the efficiency be greater than 1? Is it because COP_{\text{heating}}>COP_{\text{cooling}}

Homework Statement 1kg of moist air of RH 70% at 21oC is cooled at a constant pressure of 1 bar to 5oC. The vapour pressure at 21oC and 5oC are 0.025 bar and 0.0087 bar. The percentage of water vapour that condenses into water at 5oC is? Want to check whether my intuition & logic are correct...

I'm trying to understand why $$\left(\frac{\partial P}{\partial T}\right)_V = -\left(\frac{\partial P}{\partial V}\right)_T \left(\frac{\partial V}{\partial T}\right)_P$$ where does the minus sign come from?

Dear all, I am using molecular dynamics to calculate energy for ionic liquid. In the article that is proposed equation of state that I want to use, the author would call the energy in the following formula(u) conformational(potential energy): (du/dv)T + T(dp/dT)V = ptot Firt T and V are...

My colleague has been developing a hybrid water/forced air heat transfer system for a prototype lighting solution we are developing. I am struggling to get my head around the calculations required to figure out exactly how many watts of energy (heat in this case) are being transferred to the...

What are the math concepts I have to learn for Radiometry, Photometry and Thermodynamics (all Calculus-based) as applied in building science (engineering, architecture, etc.). I'm almost done with Multivariable Calculus and I'm aware that MV Calculus is necessary, but what specific calculus...

hi guys can you tell, how to know if steam is saturated or superheated?

Conceptually, why does infinitesimally changing a system allow for a process to be reversible. For example, if we heat a system at temperature T1 to T2 by using a heat reservoir at T2, it is considered irreversible, but if we heat the system with many reservoirs at temperatures T1+dT, T1+2dT...

Homework Statement (a) A block of copper at a pressure of 1 atm and a temperature of 5 degree celcuis is kept at constant volume. If the temperature is raised to 10 degree celcius what will be the final pressure? (b) If the vessel holding the block of copper has a negligibly small thermal...

I am looking for a graduate level textbook that would sufficiently describe the two phase flow characteristics during flow boiling. What textbook could I use to explore this topic? Is a graduate level forced convection going to cover two phase flow?

Homework Statement Two pans filled with water. Water in a 3.7cm deep pan is observed to boil at 98 degrees Celcius. At what temperature will the water in a 46.3cm deep pan boil? Homework Equations P=3.146T-211.87 (linear approximation) Water properties table: 95°C 84.609kPa .001060 vf 1.9808vg...

Homework Statement On a hot summer day, you planned a trip to a beach, but you inadvertently took a wrong turn and now you’re worried the ice in your cooler is going to melt. The cooler is 0.5 m × 0.5 m × 0.4 m, and is made with 5 cm thick Styrofoam (k = 0.033 W/m2K). Help your panicking...

Learning Radiometry, Photometry, Optics, Thermodynamics, Fluid Mechanics(Statics & Dynamics) with great resources. I'm looking for resources for understanding the topics above. I prefer video tutorials as opposed to books but I couldn't find any video resources on Photometry and Radiometry (I...

Homework Statement Homework Equations $$\frac{\partial S}{\partial u}\Bigr|_{v} = \frac{1}{T}$$ $$\frac{\partial S}{\partial v}\Bigr|_{u} = \frac{-P}{T}$$[/B] The Attempt at a Solution a.) $$\frac{S}{R} = \frac{UV}{N} - \frac{N^3}{UV}$$ $$\frac{S}{R} = \frac{UV}{N} - \frac{N}{uv}$$ $$...

Homework Statement In the image, as the first chapter of thermodynamics class, I understand all things in the answer except the highlighted part (lower bottom of the image). It is not directly related to thermodynamics but about the area ratio of the two ends of the tube, but I do not...

I am self -studying "blundell thermal physics" . But,the answers of the problems are not given in the book. So, can anyone recommend me other book with the answers? I will be thankful to you for this. Will "An Introduction to Thermal Physics by Daniel V. Schroeder" be a better option ?

Homework Statement A constant volume gas thermometer contains a gas whose equation of state is (p+\frac{a}{V^2_m})(V_m-b)=RT and another, of identical construction, contains a different gas which obeys the ideal gas law, pV_m = RT. The thermometers are calibrated at the ice and steam points...

My event description is "Create a device that retains heat prior to the event and answer thermodynamics questions". This is a high school to 1st year college level competition. I just need a textbook with the basic information on Thermodynamics as well as some information on insulation and the...

1.The problem statement: Hydrogen (H2) is at standard conditions in a closed tank, V = 5l, and then it's cooled down for 55K. Find delta U and Q. 2. Questions: If it says standard conditions, can I just use pV = nRT to find n and then deltaU = j/2*nR(delta)T? Also, is there any work that a gas...

Hello everybody, I am using an equation of state to calculate the thermodynamical properties of a material. I have a problem which is the ideal part of the equation. Actually, I cannot be sure that the ideal contribution in my equation is the really ideal contribution, so I decided to calculate...

Homework Statement The dot in Fig. 19-18b represents the initial state of a gas, and the isotherm through the dot divides the p-V diagram into regions 1 and 2. For the following processes, determine whether the change Eint in the internal energy of the gas is positive, negative, or zero: (a)...

Hi, I am a senior in high school and I want to learn more about thermodynamics and physics in general. Unfortunately, I don't have anything available at my high school. I am trying to find online courses but I honestly don't know where to look at because some of the courses I've seen seem too...

Hello, I tried attempting the following example problem 11.1(please see below), however I don't quite get from where they got cp=1.00 and cv=0.717? I know that Q=m*cp*delta T=> cp=Q/(m*delta T) Q=n*cv*delta T=>cv=Q/(n*deltaT) Problem statement Their solution: How did they...

A 2 stage compressor has a final delivery/discharge pressure of 250 bar. hydrogen is been compressed and stored in vessels. The pressure in the storage vessel reaches the delivery pressure(i.e.250 bar) and the compressor is still running ( vessel has a safety pressure of 450 bar) and the...