What is Thermodynamics: Definition and 1000 Discussions
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, radiation, and physical properties of matter. The behavior of these quantities is governed by the four laws of thermodynamics which convey a quantitative description using measurable macroscopic physical quantities, but may be explained in terms of microscopic constituents by statistical mechanics. Thermodynamics applies to a wide variety of topics in science and engineering, especially physical chemistry, biochemistry, chemical engineering and mechanical engineering, but also in other complex fields such as meteorology.
Historically, thermodynamics developed out of a desire to increase the efficiency of early steam engines, particularly through the work of French physicist Nicolas Léonard Sadi Carnot (1824) who believed that engine efficiency was the key that could help France win the Napoleonic Wars. Scots-Irish physicist Lord Kelvin was the first to formulate a concise definition of thermodynamics in 1854 which stated, "Thermo-dynamics is the subject of the relation of heat to forces acting between contiguous parts of bodies, and the relation of heat to electrical agency."
The initial application of thermodynamics to mechanical heat engines was quickly extended to the study of chemical compounds and chemical reactions. Chemical thermodynamics studies the nature of the role of entropy in the process of chemical reactions and has provided the bulk of expansion and knowledge of the field. Other formulations of thermodynamics emerged. Statistical thermodynamics, or statistical mechanics, concerns itself with statistical predictions of the collective motion of particles from their microscopic behavior. In 1909, Constantin Carathéodory presented a purely mathematical approach in an axiomatic formulation, a description often referred to as geometrical thermodynamics.
I've just transferred to a new university where they did certain aspects of thermodynamics in their first year, which is a problem because I didn't do any in my first year at the university I was previously at. I did some bits in high school but not to a very high level, so I understand the...
Is there a mathematical way to show that a dissipative (or general?) dynamical system obeys the laws of thermodynamics?
I am looking for books/sites/references, thanks for any reply.
Homework Statement
A specific type of ideal gas has a specific heat capacity at constant pressure (cp=cv+R) that is a function of temperature T, such that cp=0.5+876T, where cp has units of J/kg/K and T has units of K. The gas, which is initially at T1 = 294 K and P1 = 1x105 Pa, undergoes a...
I have a thermodynamic question which has been answered by my lecturer in a qualitative rather than a quantitative fashion.
The question is:
My question is can this be answered in a quantitative fashion? I've been trying to find a way but to no avail.
My thought process is such that using...
Homework Statement [/B]
Homework Equations
Assumptions[/B]: Closed System and Quasi-static.
p = 90 + 73,386*V -> V = (p-90)/(73,386)
v = V/m
Q - W = U2 - U1
mass balance: m = m1 = m2
The Attempt at a Solution
At state 1:
p1 = 110 kPa
V1 = (110-90)/(73,386) = 2.725*10-4 m3
v1 = V1/m1...
I keep getting this question wrong, and I am struggling to understand why this is.
Homework Statement
Homework Equations
F = p*A
Ap = π*r2
The Attempt at a Solution
Denoting patm as atmospheric force, and p0 as pressure inside the cylinder.
Firstly, a force balance on the system. Force UP =...
As shown in Figure Q1a, a frictionless, massless, piston, supported by two springs, A and B, is held by a pin in a vacuum inside a rigid-walled container. The properties of the springs are: spring constants kA = 3,859 and kB = 3,090 (in N/m), natural lengths LA0 = 0.03 and LB0 = 0.1 (in m). When...
if second law of thermodynamics is emergent and not fundamental, in the same way color is emergent but atoms themselves are colorless, then perhaps black holes do not carry entropy or can violate the second law? second law of thermodynamics is shown to exist in the macroscopic world but how do...
Homework Statement
A space probe carry an instrument that detects radiation in space, the area of the probe is ##5000 \, cm^2## and its collecting data for 10 minutes. The information sent back to Earth is given from this image below, how much radiation energy is it for 10 minutes...
Homework Statement
A boll of iron with the volume ##V=\frac{4 \pi 0.01^3}{3}## heats up to 1073 K in a chamber with vacuum, how long will it take until the iron is at 1063 K? The given data is this:
##\rho_{iron} = 7870 kg/m^3##
specific heat.. ##c_i = 0.5 \cdot 10^3 J/(kg \cdot K)##Homework...
Homework Statement
An ideal gas with pressure ##p_1=2## bar and volume ##V_1=3 \, m^3## is expanding under constant pressure to the volume ##V_2=3V_1##. Then we compress the gas isothermally back to ##V_1##. Finally the gas cools down to initial pressure ##p_1##. Calculate the total amount of...
Homework Statement
IMPORTANT:There is an error in the statement.α and β are in C not K
2. Homework Equations
R=Ro(1 +αt+βt2)
The Attempt at a Solution
I really don't know what to do because if I isolate t in the equation it will give me the temperature on the ideal gas scale whereas the...
I am having trouble with this problem. I have drawn the diagram , but don't know how I can attach it onto this post. But, for a I have COP= Qin/Wcycle = 650 J/m^2 s / Wcycle = 32.5 kW/Wcycle --> Wcycle = 10.15 kW. But,that is the wrong answer.[PLAIN]http://
Can someone please help me with the following proof ...I'm stuck and not sure if I'm even on the right path.
Prove that What I've done so far;
if U = f(T,V)
dU = (∂U/∂T)v dT + (∂U/∂V)t dV
Cv (non ideal) = (∂U/∂T)v
Using dU = TdS - PdV and Maxwell relation (∂S/∂V)t =(∂P/∂T)v,
(∂U/∂V)t =...
I found a fast solenoid valve lying around (~1ms rise time) so I thought it would be fun to hook up to a compressed air line and use to generate some really loud bass. I hooked it up to a function generator and air supply only to find that it was disappointingly quiet (well not quiet, but...
Mod note:
The link in the original post contained a link to a crackpot, anti-evolution website (against our rules) that discusses a rejected paper (also against our rules). This link has been removed. Here's a link to Retraction Watch that covers the same (retracted) paper...
A volume VA contains n mole of a bi-atomic ideal gas, initially at temperature TA. Burning an amount M of methane, whose calorific power P (produced heat per unit mass while burning) is 13271 [kcal/kg], the temperature is slowly doubled, simultaneously expanding the volume in order to maintain...
Homework Statement
Suppose a room with 75 m3 of air also contains 80 kg of glycerol and the initial temperature in the morning is 16 °C. If 1.2 kWh of heat is added to the room between morning and afternoon, calculate the final temperature of the air in the room in the afternoon.
Use 18 °C for...
I always thought that a working substance / coolant with a high heat capacity is better since it can take in more thermal energy. why then are some of the most common heat exchange fluid chemicals ones with low heat capacities?
acetone and freon for example, are commonly used heat exchange...
So, I am deeply unsatisfied with the way I've been taught E&M and thermodynamics in school. Despite having done AP Physics C: E & M and having got a 5 in it, I feel my understanding is lacking. Could you guys ( and girls) please recommend something rigorous for me to use to teach myself.Books...
Homework Statement
Suppose a room with 75 m3 of air also contains 80 kg of glycerol and the initial temperature in the morning is 16 °C. If 1.2 kWh of heat is added to the room between morning and afternoon, calculate the final temperature of the air in the room in the afternoon.
Use 18 °C for...
Inside a cylinder with a sliding piston, n mole of monoatomic ideal gas at temperature TA occupy a volume VA at pressure PA, in equilibrium. The piston is expanded very slowly, turning the pressure in such a way that the product V⋅P2 remains constant till the volume VB .
I have to evaluate the...
Homework Statement
Homework Equations
W = ∫pdV
W = (1/2)*k*(x2212)
F = p*A
The Attempt at a Solution
Assumptions made:
1. Quasistatic process.
2. Pressure is constant.
Force balance on the piston reveals
-> = <-
p0*Apiston = patm*Apiston hence p0 = patm = 101 kPa
From states 1-2...
Homework Statement
In a rigid sealed tank, 0.32kg of saturated H2O vapour is cooled from 16 bar to 2.70 bar. Determine the heat removed in Kj.
Homework Equations
Q(12)-W(12)=U2-U1
The Attempt at a Solution
Assuming that we're only looking at the saturated vapour internal energies, and there...
Homework Statement
Air enters a compressor at 100kPa and 20 oC in steady flow rate . Air is compressed to 1 Mpa. The heat loss is 10% of the power of the compressor . Air enters with speed of 50m/s in a surface of 0,009 m2 and leaves with speed 120 m/s from a surface of 0,0005 m2.
Find the...
Homework Statement
In a sample of wet steam at 11 bar, 75% of the total internal energy is contained in the vapour portion. Calculate the dryness fraction of the steam to 3 decimal places.
Homework Equations
u(kJ/kg) = (1-x)uf + x*ug
x - dryness fraction
f - saturated liquid state
g -...
I was reading thermodynamics and about Born Haber cycle. There, I found that the values given for electron affinity are positive.
When an electron is added to flourine, it attains noble gas configuration. So i t becomes more stable. So shouldn't the reaction be exothermic?
Homework Statement Air enters a compressor at 100 kPa and 290 K, where it is compressed adiabatically, where the flow rate is 0.1 kg/s. If the volume compression ratio is (V1/V2=8). Determine the following (Assuming the air is ideal with constant specific heat):
1- The temperature and the...
Homework Statement
Q1- 0.15 kg of air (Ideal) compressed in a polytropic process (PV1.5=C) from 0.06 m3 to 0.01 m3. If the initial pressure was 0.25 MPa. Determine:
1- The initial temperature and the final pressure.
2- The work done during the process.
Homework Equations
P1 V1 = m R T
P1...
Homework Statement
The steam enter the turbine (3) of the steam plant at 8 MPa and 500°C. The steam extends in an isentropic process and leaves the turbine (4) at 200 kPa, then enters and leaves the condenser at constant pressure (You may treat the steam as a saturated liquid when it leaves the...
Homework Statement
- A well insulated rigid steel tank contains water (only)
- A resistance heating element (240V, 3.67Amp) designed to heat the water as well as inlet and outlet valves for - the water.
- At state-1, the water is in a saturated liquid-vapor mixture state at P(abs)=100kPa...
Homework Statement
The formation of cadmium complexes with Br- exhibits successive equilibrium constants such that log(k1)=1.56, log(k2)=0.54, log(k3)=0.05, log(k4)=0.37.
Explain why k4 is greater than k3
Homework Equations
$$K=e^{\frac{-\Delta H}{RT}}\cdot e^{\frac{\Delta S}{R}}$$
The...
The space above the mercury column in a thermometer ordinarily is evacuated, but due to faulty manufacture, a particular thermometer has a pressure of 2 mmHg of air in this space when the whole thermometer is immersed in a bath at 0 degrees Celsius. Calculate the pressure of the air when the...
Homework Statement
The motherboard in a laptop is run by a PSU of 20V/4.5A. This motherboard is inside a plastic case where there is not heat transfer through the casing. To stop the motherboard from over heating a single (motherboard powered) 10W electric fan is mounted inside the casing.
The...
I'm taking a second course in thermodynamics and statmech, but it has always been a subject I have found unintuitive. Could anyone recommend a clear, concise textbook with a strong emphasis on mathematics/ mathematical physics? Thank you for any suggestions.
Hello!
I have some troubles finding a way to estimate how much temperature of liquid would rise when it is suddenly adiabatically pressurized to thousands of bars. In normal conditions liduids such as water are considered to be incompressible, but certainly not in 5000 bars. Because water (or...
Entropy of any system is state dependent. I just read about thermodynamics and I got this question. I first set my system which contained my classroom, the hallway connecting my physics teacher's cabin and the classroom. Then let the entropy of the system be S when I was going to the classroom...
Can anyone tell me the formula.
For example: How long does it take to boil 1kg 20°C water in steel container. With 1 kg of coal (or something). I want to understand the formula of time attitude to heat.:smile:
Homework Statement
A rigid vessel of volume 5m^3 contains 1.0 kg of water and steam at 19 degree C.Find the pressure and the mass of liquid and vapour in the vessel.
The vessel is now heated unit the water is just evaporated. Calculate the the pressure and temperature of this process. The...
1) We know that when both liquid and vapor are present, and system of these is in phase equilibrium; the "partial pressure of the vapor" must be equal to the "vapor pressure" , i.e. :
partial pressure of vapor= vapor pressure.
2) However, what happens if there is no liquid in the system, i.e...
Can someone recommend me some good textbooks or articles that contain or focus on statistical thermodynamics and/or oscillatory motion (preferably with advanced math, not just stories)?
Homework Statement
A sample of an ideal gas goes through the process shown in Figure P20.32. From A to B, the process is adiabatic; from B to C, it is isobaric with 100 kJ of energy entering the system by heat. From C to D, the process is isothermal; from D to A, it is isobaric with 150 kJ of...
I was wondering if somebody could explain to me how does the process of Enceladus being heated up satisfy the laws of thermodynamics, more precisely the conservation of energy.
Or should I ask where is the payment for the giant geysers on that moon? In layman terms, please!
Hi.
Let's say we have two separate systems (containing gases), each with their own temperature, pressure and volume. Then these systems are brought together, with no walls in between. Of course, one might consider they are now technically the same system, but the distribution of pressure and...
1.Question
I need to check if i solved it right can someone please check it , thank you. Its worth a lot of points
http://postimg.org/image/vbictz4mt/
The Attempt at a Solution
GIven
P1 = 50 kpa
T1 = -20 C = 253 K
1 to 2 is isentropic process
Therefore we can use
PT^k/(1-k) = constant
k =...
Homework Statement
max. Turbine work output rate: 6.0MW
Turbine isentropic efficiency: 90%
Turbine exit state (isentropic): 40KPa, x=92%
Turbine and pump actual process are assumed adiabatic
Find turbine inlet state: Pinlet, Tinlet, Sinlet
Homework Equations
W = ΔH
h = hf + xhfg
The Attempt...
I recently posted about a browser-based educational app that graphs the position, velocity, and acceleration of the mouse's vertical motion. In the same spirit, I've written an app that demonstrates the statistical basis of the second law of thermodynamics by simulating the free expansion of a...