Heating a room and internal energy question

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SUMMARY

The discussion centers on R. Emden's 1938 assertion that heating a room does not increase its total internal energy, specifically when the room contains an ideal gas, has a fixed volume, and variable pressure. The internal energy of an ideal gas is solely dependent on temperature, and thus, if the temperature remains constant, the internal energy remains unchanged. To maintain constant internal energy while varying temperature, the pressure must adjust inversely to the temperature, as described by the ideal gas law (PV=nRT). This relationship can be mathematically expressed through the derivation of the internal energy change per mole with respect to temperature.

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  • Understanding of the Ideal Gas Law (PV=nRT)
  • Familiarity with thermodynamic concepts, particularly internal energy
  • Knowledge of state variables in thermodynamics
  • Basic calculus for deriving equations
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  • Study the implications of the Ideal Gas Law on internal energy changes
  • Learn about thermodynamic processes and their effects on state variables
  • Explore the concept of internal energy in different thermodynamic systems
  • Investigate the relationship between temperature, pressure, and volume in fixed-volume systems
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sbdavinci
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Hi, I am having a hard time answering this question. Any help will be appreciated.
In 1938, the journal Nature published a paper by R. Emden titled “Why do we have winter heating?” (Nature Vol 141 pp. 908-9 – although you do not need to read it to answer the problem). This article asserts that heating a room does not increase the total internal energy of the room. Examine this assertion assuming:

(a) the room is filled with an ideal gas
(b) the volume of the room is fixed
(c) the pressure of the room is variable and set by the external atmosphere.
(i) Show that the internal energy of the room is independent of the temperature of the room!
(ii) What state variables change with temperature in order to maintain constant internal energy? How are they affected by temperature (derive an equation to describe this)?

Thank you
 
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Based on the assumptions for constant values in the statement: If you rearrange the ideal gas equation to substitute the variable terms in the formula for internal energy, maybe you are able to see how the internal energy changes with varying temperature.
 
If the temperature rises by ΔT, what is the change in the internal energy per mole? If the temperature rises by ΔT, what is the change in the number of moles of gas in the room?

Chet
 

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