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
The variable u represents the internal energy of a system, q represents the heat added to the system, and w represents the work done by the system.
The equation u = q + w is a mathematical representation of the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system.
No, this equation is only applicable to closed systems where there is no transfer of matter. For open systems, the equation must be modified to include the change in mass of the system.
Yes, this equation can be rearranged to solve for either q or w by subtracting one variable from both sides and then dividing by the remaining variable. For example, q = u - w or w = u - q.
This equation is used in various fields, including thermodynamics, chemistry, and physics, to calculate the internal energy of a system and to determine the amount of heat and work involved in a process. It is also used in engineering applications, such as in the design of heat engines and refrigeration systems.