# What is Equilibrium temperature: Definition and 47 Discussions

The planetary equilibrium temperature is a theoretical temperature that a planet would be a black body being heated only by its parent star. In this model, the presence or absence of an atmosphere (and therefore any greenhouse effect) is irrelevant, as the equilibrium temperature is calculated purely from a balance with incident stellar energy.
Other authors use different names for this concept, such as equivalent blackbody temperature of a planet, or the effective radiation emission temperature of the planet. Planetary equilibrium temperature differs from the global mean temperature and surface air temperature, which are measured observationally by satellites or surface-based instruments, and may be warmer than an equilibrium temperature due to greenhouse effects.

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1. ### What happens to the IR radiation that the Greenhouse gases don't absorb?

I have been searching for the answer yet – as I'm here – didn't find it. The current model of climate warming says the lower parts of Earth's atmosphere don't allow the IR radiation to escape freely to the outer space because the GH gas molecules keep absorbing it virtually as soon as it's been...
2. ### SO2 Conversion Equilibrium Curve

Hi... i want to draw Equilibrium curve for SO2 oxidation to SO3, i found following relations but don't know to use them... kindly tell me how to draw Equilibrium curve using these equations or any source on web from where i can get directly SO2 oxidation data Vs Temp? Equations are following...
3. ### Finding equilibrium temperature when there are phase changes

If there weren't phase changes occurring I know that the temperature equilibrium would be ##T_e=\frac{m_{ice}c_{ice}T_{ice}+m_{w}c_{w}T_{w}}{m_{ice}c_{ice}+m_{w}c_{w}}##. Now, by repeating the reasoning to get the above formula (##\sum \Delta Q=0##) and adding the phase changes of the water...
4. ### Equilibrium temperature in a homogeneous section (stationary regime)

I believe it is just an arithmetic medium, but I am not sure. Could someone explain to me?
5. ### Chemistry Equilibrium temperature of a water and ice system

Equal masses of ice at –10ºC and water at 80ºC are placed in an insulated container and allowed to reach thermal equilibrium. Calculate the equilibrium temperature Data: Water(ice): 37,65 J/mol.K Agua (l): 75,29 J/mol.K ## Lf = 6011 J/mol ## I solved it this way: ## -Q_{l} = Q_{ice} ## ##...
6. ### Statistical Mechanics: Two systems reaching an equilibrium temperature

First I found partition functions of both the systems and hence total energies of them using above formulas. Z(A) = (1 - e-ε/kT)-1 and Z(B) = (1 + e-ε/kT) Then I equated these values to the given values of total energies. I got: For System A, T(A) = ε/kln(2) > 0 For System B, T(B) =...
7. ### Black cube, maximal and minimal value of equilibrium temperature T

So i had this problem and I want a rigourous solution. The answer should be : Tmin=(I/sigma)^(1/4) and Tmax=(sqrt(3I)/sigma)^1/4
8. ### Find the equilibrium temperature & the amount of ice/water

That's how far I've gotten and now I'm stuck!
9. ### Solving for Final Equilibrium Temperature of Water-Copper System

Homework Statement 173 g of water at 20°C is contained in a copper container of mass 327 g. An additional 129 g of water at 100°C is added. What is the final equilibrium temperature (in degrees C) if we treat the system's water and container as isolated? Homework Equations Q = mcΔT The...
10. C

### Equilibrium Temperature with three substances

Homework Statement If a block of 250 grams of lead (specific heat (c) =130) at 315 degrees celsius is placed in a 200 gram aluminum (c=900) calorimeter cup containing 900 grams of water (c=4.1), and the calorimeter and the water are both initially at 15 degrees celsius, what is the equilibrium...
11. ### What is the equilibrium temperature of a collector plate?

Homework Statement You would like to put a solar hot water system on your roof, but you're not sure it's feasible. A reference book on solar energy shows that the ground-level solar intensity in your city is 750 W/m^2 for at least 5 hours a day throughout most of the year. Assuming that a...
12. ### Equilibrium temperature of some ice and steam

Homework Statement "A well-insulated bucket of negligible heat capacity contains 120 g of ice at 0°C. If 20 g of steam at 100°C is injected into the bucket, what is the final equilibrium temperature of the system?" Homework Equations $$Q_{fus} = m_{water}L_{fus}$$ Q_{vap} =...
13. ### I Understanding Thermalisation in Particle Systems

I've recently been reading a bit into the thermalisation of a system of particles and I'm unsure on a couple of concepts. Firstly, if a system of particles are out of mutual thermal equilibrium, does this essentially correspond to the particles in the system having randomly distributed momenta...
14. ### I Why do we need "planetary equilibrium temperature"?

I mean, currently it seems that scientists are using equilibrium temperature of exoplanets (calculated assuming an Earth-like albedo) to determine whether a planet is habitable or not. But aren't there other more accurate ways to determine surface temperatures of exoplanets? I learned Wien's...
15. ### Thermal Equilibrium Temperature Question Sodium and Water

Homework Statement Expose the error: When sodium is placed in water, a violent reaction always occurs; therefore sodium and water can never be at the same temperature. Homework Equations Thermal equilibrium and temperature. Zeroth law. Isotherms. The Attempt at a Solution My Answer: The...
16. ### Greenhouse effect on planetary equilibrium temperature help

I am trying to back-calculate the greenhouse effect on planetary equilibrium temperature for Earth (in the hope I can then attempt applying it to other calculations.) I know that the actual equilibrium temperature of Earth is 287.89K, +33K above the calculated equilibrium temperature: Teq = (Q...
17. ### Equilibrium temperature of three different substances

I've been asked to find the final temperature of different in an insulated container. A combination of 0.25kg water at 20C, 0.4kg aluminum at 26C, and 0.1kg copper at 100C are combined, and allowed to come to thermal equilibrium. Finding the equilibrium temperature for two substances is...
18. ### Equilibrium temperature with 2 states of matter

35g of h2o(g) at 380K flows into 300g of h2o(l) at 300K. Cp(l)=4.18kJ/K*kg and ΔH(condensation)= -2257kJ/kg. I need to calculate the final temperature when the system reaches equilibrium. Is the heat capacity for the h2o gas different than h2o liquid? Can you calculate heat capacity using...
19. ### How to find equilibrium temperature of a system

Homework Statement A gas is in an insulated box, which is divided into two portions by an insulated partition. There are n1 moles of the gas at temperature T1 in volume V1, and likewise n2 moles of the (same) gas at temperature T2 in volume V2. The partition is composed of two layers; one...
20. ### Equilibrium temperature of a mixture

Homework Statement Homework Equations Q = m c \Delta T \\ Q = m L_v \\ Q_{in} = Q_{out} The Attempt at a Solution m_s c_s (100 - 8) + m_s L_v = m_s c_s (100 - T) + m_m c_s (T) \\ 5778.06 + 33900 = 5778.06 - 62.805 T + 418.7 T \\ 33900 = 355.895 T \\ ∴ T = 95.25°C Answer should...
21. ### Find the Equilibrium temperature distribution of a PDE

Homework Statement 1) What is the Equilibrium temperature distributions if α > 0? 2) Assume α > 0, k=1, and L=1, solve the PDE with initial condition u(x,0) = x(1-x) Homework Equations du/dt = k(d^2u/dx^2) - (α*u) The Attempt at a Solution I got u(x) = [(α*u*x)/2k]*[x-L] for...
22. ### Equilibrium temperature distribution in gravitational field

I came across Tolman's paper on the equilibrium distribution of temperature in gravitational field. He argues that in contrast to classical thermodynamics situations, in gravitational field, a fluid in thermodynamic equilibrium will not have the same temperature everywhere (as measured by...
23. ### Calculate Equilibrium Temperature

Homework Statement A 1kg of ice at -30° C is added to 10 kg of steam at 500°C. answer the following questions: a) What is the final phase of the system of ice + steam if no heat escaped from it. b) What is the final temperature when the equilibrium is established Homework Equations...
24. ### Finding the equilibrium temperature of a mixture substances

Homework Statement 160g of steam at 100°C is added to 1000 g of ice at 0°C. What is the equilibrium temperature of the mixture? Assume the container has a negligible heat capacity. Homework Equations Qloss+Qgain=0;[m*c(delta T)] + [m*c(delta T)] = 0 The Attempt at a Solution i...
25. ### Finding equilibrium temperature of water and a solid

Homework Statement If 100 grams of glass (specific heat .2 cal/g*°C) at a temperature of 500 °C is added to 20 g of 0°C water, what is the final equilibrium temperature? Homework Equations Q= mcΔT The Attempt at a Solution I know that I have to set the two equation against...
26. ### Final Equilibrium Temperature

Homework Statement An adiabatically isolated system consists of 1 mol of a diatomic gas 100K and 2 mol of a solid at 200K separated by a rigid adiabatic wall. Find the equilibrium temperature of system after adiabatic wall is removed, assuming that the solid obeys the Dulong-Petit law...
27. ### Radiative equilibrium temperature of a satellite

Homework Statement A small, perfectly black, spherical satellite is in orbit around the Earth. If the Earth radiates as a black body at an equivalent blackbody temperature T_{E} = 255 K, calculate the radiative equilibrium temperature of the satellite when it is in the Earth’s shadow. Start by...
28. ### Equilibrium temperature distribution for rod of 2 materials

1. Determine the equilibrium temperature distribution for a one-dimensional rod composed of two different materials in perfect thermal contact at x=1. For 0<x<1, there is one material (c\rho=1, K=1) with a constant source (Q=0), whereas for the other 1<x<2 there are no sources (Q=0, c\rho=2...
29. ### CBR photon density at equilibrium temperature

CBR photon equilibrium temperature: T_{\gamma} = 2.725 \; \text{K} CBR photon density at equilibrium temperature T_{\gamma}: n_{\gamma} = \frac{1}{\pi^2} {\left(\frac{k_B T_{\gamma}}{\hbar c}\right)}^3 \int_0^\infty \frac{x^2}{e^x - 1} dx This is my solution for the integration equation...
30. ### Help calculating equilibrium temperature for a reaction

I am supposed to find out the adiabatic equilibrium temp. of a liquid phase hydrolysis reaction where the reactants are fed stoichometrically at 20 degrees Celsius. I know I need to find out the Keq for this reaction, but I have no idea how to go about calculating Keq without concentrations of...
31. ### Equilibrium temperature and Dulong-Petit law

Homework Statement A thermally insulated system consists of 1 mole of a diatomic ideal gas at 100K and 2 moles of a solid at 200K that are separated by a rigid insulating wall. Find the equilibrium temperature of the system after the insulating wall is removed, assuming the solid obeys the...
32. ### Finding Thermal Equilibrium Temperature

Homework Statement A 1.5 m3 tank containing air at 35°C and 750 kPa is connected by a valve to another tank containing 8.25 kg of air at 65°C and 265 kPa. Now the valve is opened and the entire system is allowed to reach thermal equilibrium with the surroundings, which is at 25°C. Determine...
33. ### Equilibrium temperature of heat exchanger

In a closed loop with a heater and a fan cooled finned heat exchanger where water flows between the two, is it right to assume that the water will reach an equilibrium temperature? If so, is there an equation that can get the equilibrium temperature? The power of the heater and cooler, the...
34. ### What Is the Equilibrium Temperature When Aluminum Meets Water?

Homework Statement A 150g aluminum cylinder is removed from a liquid nitrogen bath, where it has been cooled to -196 degrees C. The cylinder is immediately placed in an insulated cup containing 60.0g of water at 15.0 degrees C. What is the equilibrium temperature of the system? Homework...
35. ### Equilibrium Temperature and composition

Homework Statement Describe the composition and temperature of the equilibrium mixture after 1.0 kg of ice at -40*C is added to 1.0 kg of water at 5.0*C.Homework Equations \begin{gathered} Q = mc\Delta T \hfill \\ Q = mL \hfill \\ \end{gathered} Book answer:1.2kg ice, 0.80 kg water...
36. ### How do I calculate the equilibrium temperature of a system?

I've found the question that I am doing at this site: http://www.kent.k12.wa.us/pcpow/questions/phys/0105Bird/index.html The answer is given here, but not the steps: http://www.kent.k12.wa.us/pcpow/solutions/physics/0105bird/index.html I know how to do Part A, but no matter how I...
37. ### What is the Equilibrium Temperature When Mixing Hot and Cold Water?

When 1 kg of water at 100degC is mixed with 10kg of water at 0degC, the equilibrium temperature will be: a)exactly 0degC b)exactly 50degC c)exactly 100degC d)slightly above 0degC if anyone can post the formula to use for this that would be great! thanks!
38. ### What is the equilibrium temperature of copper and water?

I am not a novice at thermodynamics but still the following question made me think over my status more than twice. I have to find the equilibrium temperature when a 50 Kg block of copper at 80C is placed in a container which as 120L of water at 25C. I made simple equations of heat lost =...
39. ### Finding the Equilibrium Temperature

Homework Statement following on from my thread in the Nuclear physics subforum, I am trying to work out the equilibrium temperature of three isotopes (Neon) in a state of equilibrium established by thermal contact with a bath of neutrons at a temperature T. Homework Equations...
40. ### Equilibrium temperature homework

4. When 1 kg of water at 1000C is mixed with 10 kg of water at 00C, the equilibrium temperature will be: a) exactly 00C b) exactly 500C c) exactly 1000C d) slightly above 00C 5. Two objects, A and B, have the same mass and the same initial temperature. However, object A has a...
41. ### Equilibrium Temperature of water in cup

Homework Statement A 37 g ice cube at 0.0°C is added to 110 g of water in a 62 g iron cup. The cup and the water have an initial temperature of 40°C. (a) Find the equilibrium temperature of the cup and its contents. Homework Equations I think a relevant equation is (m Lsubf) + (mc...
42. ### Equilibrium temperature of ice, water, and iron cup

so there're: 0.041 kg ice cube at 0.0 *C 0.110 kg water at 40.0 *C in 0.062 kg iron cup at 40.0 *C Find the equilibrium temperature of the cup and its contents: ------- So what I tried doing was... I found the heat lost by water if cooled to 0 *C, which was 18418.4 J (mass of water *...
43. ### What is the equilibrium temperature of a system containing ice and steam?

An insulated bucket contains 150 g of ice at 0°C. If 26.0g of steam is injected at 100°C into the bucket, what is the final equilibrium temperature of the system in °C? this i what I've done so far q(ice)=150g*333.5J/g=50025J q(steam)=26g*2257J/g=58682J q(ice) + q(ice-water) =...
44. ### Calculating Equilibrium Temperature in a Water Mixture

How would you find the equilibrium temperature in a problem like this? **I don't need the answer, just some advice on getting there** 45g of water at 4 degrees C is added to 150g of water at 75 degrees C. What is the mixture's equilibrium temperature?
45. ### What Went Wrong in Calculating Equilibrium Temperature?

A 199 g lead ball at a temperature of 80.9°C is placed in a light calorimeter containing 178 g of water at 24.5°C. Find the equilibrium temperature of the system. i used the equation Q = mc \Delta T -(199g)(4.186J/g°C)(T - 80.9°C) + (178g)(0.13J/g°C)(T - 24.5°C) = 0 T = T final = 82.5°C...
46. ### What is the final temperature of a mixture of steam and ice?

:yuck: I keep getting 16 degrees for the temp.. This isn't the right answer... Can anyone help?? Steam at 100 degrees C is added to ice at 0 degrees C. The mass of the steam is 10.0g and the mass of the ice is 50g. What is the final temperature of the mixture.
47. ### Equilibrium temperature as function of latitude

Find the equilibrium temperature of the moon as a function of latitude assuming that the moon is a rapid rotater with an emissivity of 1, zero obliquity, and a bond albedo of 0.07. The only variable for this problem in the equation for equilibrium temperture is the distance from the Sun. If...