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ideal gas a nd Thermodynamics

Why temperature of an ideal gas increases without any thermal energy being added ? Ans: An ideal gas is a theoretical concept used to describe the behavior of gases under certain conditions. According to the ideal gas law, the temperature of an ideal gas is proportional to the average kinetic energy of its particles. If the temperature of an ideal gas increases without any thermal energy being added, this means that the average kinetic energy of its particles must have increased.

There are several ways in which the average kinetic energy of the particles in an ideal gas can increase without adding thermal energy:

  1. Compression: If the volume of an ideal gas is decreased (compressed), its pressure will increase, and so will the average kinetic energy of its particles.

  2. Expansion: If the volume of an ideal gas is increased (expanded), its pressure will decrease, and so will the average kinetic energy of its particles.

Explain why the latent heat of vaporisation is much greater than latent heat of fusion for same substance? explain in terms of spacing of molecules

Ans:

The latent heat of vaporization is greater than the latent heat of fusion for the same substance because the process of vaporization involves breaking the intermolecular bonds that hold the molecules together, whereas the process of fusion only involves rearranging the molecules in the solid phase to form a liquid.


The intermolecular bonds in a solid are much stronger than in a liquid, as the molecules are packed closely together in a solid and are in fixed positions relative to each other. In contrast, the molecules in a liquid have more freedom to move and have weaker intermolecular bonds. As a result, breaking these bonds requires a much greater amount of energy than simply rearranging them, which results in a much larger latent heat of vaporization.


In terms of molecular spacing, the vaporization process involves changing the state of matter from a compact solid or liquid state to a gaseous state, where the molecules are much farther apart from each other and have a much greater degree of freedom to move. This increase in spacing requires the input of a large amount of energy to overcome the intermolecular bonds, resulting in a higher latent heat of vaporization.

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