Heat capacity Definition and 439 Threads

Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K).
Heat capacity is an extensive property. The corresponding intensive property is the specific heat capacity, found by dividing the heat capacity of an object by its mass. Dividing the heat capacity by the amount of substance in moles yields its molar heat capacity. The volumetric heat capacity measures the heat capacity per volume. In architecture and civil engineering, the heat capacity of a building is often referred to as its thermal mass .

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  1. I

    Heat integral and molar heat capacity?

    dQ = nCvdT if volume is constant. However, n = pV/RT. What I don't understand is, why are we thinking n as constant when doing the integral? I had two problems that involved this on a test I had today. At first I kept it constant and then changed n. But then I thought, wait... isn't there a T...
  2. E

    Calorimetry(determination of specific heat capacity)

    can we determine a specific heat of a sample by cooling it to the temperature of ice rather than heating it to the boiling point of water?
  3. A

    Statistical Mechanics - Specific Heat Capacity

    Homework Statement Give an physical explanation to why the specific heat capacity goes to zero as temperature goes to zero. Homework Equations The Attempt at a Solution I was simply thinking that around absolute zero the average kinetic energy of the particles should be zero...
  4. J

    Heat capacity of air at low temperatures

    Hello, would someone know where can one find tabulated values for the heat capacity of air c_{p} or the ratio \gamma = c_{p}/c_{v}? I need those at low temperatures and pressures, e.g. tending towards zero. So far I was only able to find \gamma tabulated for high pressures in Perry's...
  5. S

    Thermal physics; specific heat capacity

    Homework Statement In an experiment to measure the temperature of the flame of a Bunsen burner, a lump of copper of mass 0.12 kg is heated in the flame for several minutes. The copper is then transferred quickly to a beaker, of negligible heat capacity, containing 0.45 kg of water, and the...
  6. C

    How to calculate heat capacity of supercritical CO2

    Hello, 1. How can I calculate the heat required to raise the temperature of Carbon dioxide. It is at -40C and then it is to be heated to 50 C... The operating Pressure is above critical, so when it crosses the critical temperature point, the liquid CO2 would change into super critical state. (I...
  7. GRB 080319B

    Specific heat capacity and themal conductivity

    Can a compound have a high specific heat capacity and be a good thermal conductor, or are these properties mutually exclusive?
  8. P

    Specific Heat Capacity Experiment

    So our teacher wants us to find the temperature of a flame of a bunsen burner. To do so, he told us to do the following: Heat an aluminium block of known mass (160g), but unknown initial temperature. Drop it in a beaker with 500 ml of water, of known temperature (22 degrees) and let the...
  9. Telemachus

    Molar heat capacity (Thermodynamics)

    Homework Statement Hi there. I'm having some trouble on solving this exercise, which you can find on Callen 2nd edition. A simple fundamental equation that exhibits some of the qualitative properties of typical crystaline solids is: u=Ae^{b(v-v_0)^2}s^{4/3}e^{s/3R} Where A,b, and v0 are...
  10. S

    Calculating Heat Capacity for Cage Weight of 1000 kg at 9 m/s

    Homework Statement in the absense of bearing friction a winding engine would raise a cage weighing 1000 kg at 10m/s, but this is reduced by friction to 9 m/s, how much oil, initially at 20 C is required per second to keep the temperature of the bearing down to 70 C (specific heat capacity...
  11. S

    The difference between the entropy and the heat capacity? they are very similar

    the difference between the entropy and the heat capacity? they are very similar! hello ... as we all know that specific heat capacity = joule/ k entropy = joule/k they are same in units Q= m Cv dT Q/dT=m Cv...1 dS= dQ/T ...2 from 1 & 2 dS= m Cv .....??… I'm now confused...
  12. P

    Investigating Specific Heat Capacity with Boiling & Warm Water

    I am doing a lab about specific heat. i have a cup of boiling water which i put 5 metals into, and a cup of warm water which sits at 22 degrees celcius. i am to record the difference in temperature as i am using the equation Q = mc (delta) T for part one, and then i am using the equation C = Q/m...
  13. V

    How to Calculate the Specific Heat Capacity of an Unknown Metal

    Homework Statement How can you calculate the specific heat capacity of an unknown metal? In my question the metal with a mass of 50g and a temperature of 200 degrees celsius was placed in 125 g of water with an initial temperature of 20 degrees celsius. After the simulation and the metal...
  14. C

    What is the Specific Heat Capacity of Copper in Water?

    Homework Statement This was a LAB assignment. I need to find the specific heat capacity of a given metal (Cu in this case) in water, I have the following observations. Mass of water: 249.14g = 0.24914 Kg Initial temperature of water: 18 C Initial temperature of metal: 100 C Specific heat...
  15. A

    What Determines the Equilibrium Separation Between Atoms in a Lattice?

    Homework Statement [/b] Debye considered atoms to oscillate from 0 up to a nu max. It is explained further in the text that the complication (i.e., not all atoms oscillating at same frequency as shown in Einstein's formula) is accounted for, by averaging over all the frequencies present...
  16. S

    Effect of electrical field on heat capacity

    Homework Statement Given the perfect gas molecules with permanent electrical dipole moment u in the field \epsilon. The potential energy is U = -u\epsilon\cos\Theta Derive the additional effect of \epsilon on the heat capacity. I need some hints, please help. Thanks.
  17. B

    How do I calculate heat lost by the hot water in a calorimeter?

    Homework Statement 1. Calculate heat lost by the hot water in the calorimeter. Initial temp: 22.90 C Finial temp: 23.25 C Density: 1.00 g/mL specific heat capacity: 4.18 J/gK Homework Equations qmetal=-(qwater+qmetal) q=m C dT The Attempt at a Solution When i use the second...
  18. D

    How Does Pressure Affect Heat Capacity in Identical Systems?

    I understand that the heat capacity of something run at constant volume is lower than at constant pressure, as at constant pressure the substance can expand, so some of the energy put into the system is used for work. If i have two identical systems and heat them under constant pressure...
  19. O

    How to solve this photoelectric equation involving specific heat capacity

    We have the parameters,current =10^-3A,V=15kv,number of electrons=6.25 X 10^15,velocity=7.3 X 10^7,specific heat capacity of the liquid=2 X 10^3,c=3 X 10^8,h=6.63 X 10^-34,mass of electron = 9.11 X 10^-31. Now the question says,in an x-ray tube having those parameters,find the rate at which...
  20. T

    What is the final temperature of the aluminum can after heating water?

    Homework Statement 1.0 g of water at 28 degree celcius is placed into a 200g aluminium can at 300 degree celcius. What is the temperature of the aluminium can after all the water vapourises? Given the specific heat capacity of aluminium, 900 J/kg/degree celcius and water, 4200 and specific...
  21. P

    Does Specific Heat Capacity Affect the Speed of Heat Transfer in Calorimeters?

    Homework Statement This is a problem I made myself and it's really confusing me. You have 100mL of water and place it in a calorimeter of low specific heat capacity. You put another 100mL of water in another calorimeter of high specific heat capacity. Assume in both instances that the water is...
  22. G

    Heat Capacity Calculation Check.

    Hello PF, Is the following calculation correct for the amount of time it would take to raise the temperature of a given mass of material? Q = heat in J W = watts m = mass in kg c = specific heat in J/kgC Tf = temperature final Ti = temperature initial Q = m * c * (Tf - Ti) m = 5...
  23. Q

    Partition function and heat capacity

    Homework Statement QN1. A system consists of N weakly interacting subsystems. Each subsystem possesses only two energy levels E1and E2, each of them non-degenerate. Obtain an exact expression for the heat capacity of the system. QN2. A system possesses three energy levels E1 =E , E2 =...
  24. D

    Adiabatic, Ideal gas, changing heat capacity, work calculation

    1. Propane vapour (1kmol) at a pressure of 40 bar and 230 C expands adiabatically to 0.25 bar and 95 C. Determine a)W, b)Delta S, c)The amount of work obtained if the expansion were done reversibly from the same initial conditions to the final pressure of 0.25bar 2. I am not sure how to...
  25. B

    Solving for Tpeak in Heat Capacity Question | Homework Help

    Homework Statement please see attached! :) Homework Equations The Attempt at a Solution Ok so I've done the first part and the first bit of the second, so I've shown that theta = 2 uBB/kb My problem is in the next bit where it asks you to work out Tpeak. I guess you have...
  26. G

    Heat capacity at constant volume

    Homework Statement The question asks whether it is always true that dU=C_VdT and their answer is no, because from the 1st law of TD we derive that: dU=C_VdT+\left(\frac{dU}{dV}\right)_TdV However, if we hold the volume constant, dV=0 and therefore the second term disappears, is this...
  27. J

    Heat Capacity: Units, Mols & Avogadro's Constant

    I have the equation for heat capacity for constant volume and pressure. Cv = Cp -R So for Cp I have the units J/k and for R the units are J/k mol. So my question is related to that mol. Is it right that I need to get rid of that mol? if so how? Does it involve Avogadro's Constant? Or do...
  28. L

    Contribution to the heat capacity of vibrational energy levels.

    Homework Statement The carbon-dioxide has nondegenerate vibrational energies εr=（h/2π）ω(r+1);r=0,1,2..., where ω=(1.26*10^14)s^-1. What is the contribution of these vibrational modes to the molar heat capacity of carbon-dioxide gas at T=400K? Homework Equations...
  29. P

    Improving Specific Heat Capacity Experiment

    The question involves testing the Specific Heat Capacity of an aluminum block, using the equation: Q = m x Specific Heat Capacity x Change in Temperature. Two experiments are performed using the same power of the heater and the same mass of the object and a very similar change in...
  30. M

    Finding the Specific Heat Capacity

    Homework Statement The experiment was that we heated a beaker with water in it, and also a type of metal for around 5 minutes so that the metal becomes the same temperature as the water. We then dropped that heated metal into a stryofoam cup containing 189.10g of water in it. mass of...
  31. I

    Heat Capacity of Air and Energy needed

    Trying to determine the amount of energy required to heat a specific volume of air by a certain change in temperature. So far this is what I gotten. Vol: 10,000 cubic feet = 283.17 m^3 Orig Temp: 0C (32F) Final Temp: 21.1C (70F) deltaT: 21.1 K or C Density of air @ 0C: 1.293 kg/m^3 Cp...
  32. D

    Why is specific heat capacity less?

    Hi, I just did a specific heat capacity test using a calorimeter, and the specific heat capacity I found (using heat gained = heat lost) is less than the real value. The problem is, I expected it to be more. I mean heat will be lost through the calorimeter, meaning that a greater amount of...
  33. P

    Electron and phonon contribution dependence on temperature for heat capacity

    Hi there! So I'm aware that the phonon contribution is proportional to T^3 and for electrons it is T (this is for metals where the first result comes from the Debye model). I was wondering where the electron contribution is derived from and why it is such a low dependence.
  34. D

    Why is rotational energy not included in the Hamiltonian for an ideal gas?

    When using the equipartition theorem to derive the heat capacity of an ideal gas, you have \left\langle H \right\rangle=\left\langle \frac{1}{2}m\left(v^{2}_{x}+v^{2}_{y}+v^{2}_{z} \right) \right\rangle and each degree of freedom contributes 1/2 kT to the total energy and 1/2 k to the total...
  35. P

    What Is the Specific Heat Capacity of Cream?

    Homework Statement The cream is kept at 5 ºC in the lorries. It is pumped into silos, where it is pre-heated before being pasteurized. The silos are jacketed, and hot water is pumped through the jacket. Assuming no losses, if 300 kg of water at 90ºC enters the jacket and exits at 60 ºC...
  36. M

    Formulas for Molar Heat Capacity at Constant Pressure/Volume

    Homework Statement Just wanted to find some clarity regarding this subject. In my textbook, it states that Q = nCvdT for constant volume and Q = nCpdT for constant pressure. However, one of the TA's in my classes were telling us how dU = nCpdT for constant pressure and dU = nCvdT for...
  37. P

    Solving Heat Capacity Problem: 60K to 80K

    Homework Statement In the temperature range from 60 K to 80 K, a certain amount of liquid has a temperature dependent heat capacity that is given by Cp = 20 J K−1 + T × 0.5 J K−2. Determine the entropy change resulting from heating this sample from 60 K to 80 K. Homework Equations...
  38. V

    Finding Formulas for Heat Capacity

    Homework Statement I'm needing to write a program for thermodynamics, but before I can write the program, I need to find formulas for the heat capacity of a few substances: Al, Fe, BaTiO3, and Polyethylene. Ideally, I'm looking for equations that explain this behavior between 298K and 600K...
  39. P

    Calculating Heat Capacity, deltaU and deltaH of Cu Metal

    Homework Statement At 25C Cu metal (at. wt. 63.54 g/mol) has a molar heat capacity of 24.4 J/molK. The density of Cu is 8.949g/cm^3 at 0C and 8.904 g/cm^3 at 100C. Assuming that Cp is temperature independent, calculate Q, W, deltaU and deltaH when 100grams of Cu metal are heated from 0C to...
  40. M

    What determines the specific heat capacity of a given substance?

    I'm fascinated with physics and probably know at least the nature of any effect or object in classical physics, but um... I have never in any textbook or article seen mention of what determines the specific heat capacity of a given substance. Which is kinda peculiar and confusing at the same...
  41. G

    Specific Heat Capacity and Specific Latent Heat

    Hi Everyone :smile: I have to create an experiment for my assignment in Physics. I've chosen to do something about Specific Heat Capacity. A boy in my class is also doing SHC so I wanted to make mine a little different from his. I've just recently joined physics (never done it before)...
  42. E

    Statistical mechanics: Heat capacity

    I am trying to work out the heat capacity of a body-centered cubic iron lattice using stat.mech., but am having some trouble. Firstly, I assumed that the iron atoms behaved as harmonic occilators, not taking electronic or nuclear spin into account. Is this a good or bad approximation? Then...
  43. C

    Total heat capacity of an monatomic gas?

    when working this out, is it just Cv + Cp? giving 4nR? thanks
  44. Y

    Question about determing specific heat capacity using waterfall.

    Homework Statement The temperature at the top of a popular waterfall is 22.0 degrees celcius. The temperature at its base, 210 m lower, is 22.5 degrees celcius. 1)Caluclate the specific heat capacity of the water. 2) If the waterfall was twice as tall, determine by how much the water...
  45. F

    Conductivity and heat capacity of tranparent ceramics

    Hello, I want to study transparent alumina and zirconia and I wonder if they have the same conductivity and heat capacity than the dense and opaque materials ? As I can only find datas for the common materials (e.g. dense opaque ones) it would be great! My point of view is that the...
  46. P

    How Do You Calculate Specific Heat Capacity and Latent Heat of Fusion for Lead?

    Homework Statement 3.00 kg of molten lead is allowed to cool until is has solidified. It is found that the temperature of the lead falls from 605 K to 600 K in 10 s, remains constant at 600K for 300 s, and then falls to 595 K in a further 8.4 s. Assuming that the loss of heat energy remains...
  47. C

    Debye internal energy for heat capacity

    I'm working from Feynman's definition of internal energy for the Debye theory of heat capacity. I'm trying to use that to derive the normal definition of heat capacity that I've seen. But I'm running into a problem. Note, in the following V_0 is frequency, whereas V is volume (that's how Feynman...
  48. Z

    Heat Capacity in Adiabatic Vessels: Corrections for Errors

    just trying to get my head around heat capacity here for an experiment; if conducting a reaction in an adiabatic vessel, of which its material has a finite heat capacity, does this mean that if sufficient heat is produced within the vessel (through a chemical reaction), that the adiabatic...
  49. L

    How Do You Calculate Heat Capacity and Specific Heat in Chemistry Problems?

    hey for this question If a 2kg sample of aluminium absorbs 64.4 kJ of heat from its surrounds by how much does its temperature increase the answer is 65.1 how? i got 32.5 q=mcT T=q/mc=(64.6x10^3)/(2000x.9930) also same for this question If 0.5g of an organic compound is completely...
  50. J

    How to Calculate the Average Molar Heat Capacity of NaCl at Low Temperatures?

    Homework Statement The molar heat capacity at a constant volume of a solid at low temperatures T << Td, where Td is the Debye temperature is given by: C_v = 464(\frac{T}{T_d})^3 Consider Td = 281 K for the NaCl. (a) Calculate the average molar heat capacity \bar{C_v} of the NaCl between...
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