The discussion centers on the thermodynamic principles governing the phase changes of liquids and gases, specifically vaporization and condensation. When a liquid vaporizes, the energy calculated by the formula q = m x lv is not lost but rather transformed, as dictated by the first law of thermodynamics. During vaporization, the internal energy of the gas increases due to the breaking of molecular bonds, while condensation results in heat being released as the gas transitions back to a liquid, thereby decreasing its potential energy.
PREREQUISITESStudents of thermodynamics, physicists, and engineers interested in understanding energy transformations during phase changes in substances.
The first law of thermodynamics says that it cannot be lost: [itex]\Delta Q = \Delta U + W[/itex]. The heat flow of vaporization has to be equal to the work done by the gas plus the change in internal energy of the gas.jackcie said:when a liquid vaporises to a gas,
q = m x lv
this energy is lost?
It depends on the gas. When water vapor condenses heat flows out of the gas with the loss of molecular potential energy and work is done on the gas by the surroundings as the volume decreases.also, what does this mean for when a gas turns to a liquid is q added to the system, or lost (added i presume??)
cheers
jackcie said:when a liquid vaporises to a gas,
q = m x lv
this energy is lost?
also, what does this mean for when a gas turns to a liquid is q added to the system, or lost (added i presume??)
cheers