The First Law 课堂版.pptVIP

thermodynamics The science which is concerned with heat and work, and transformations between the two. Every one has learned the physical chemistry and known about the three laws of thermodynamics What can I DO FOR YOU? The first law the principle of conservation of energy; that is, energy can be neither created nor destroyed. dW+dQ is dU A Sonnet to First Law How could I have doubted your constancy your warmth and labors summed, signify your ever unchanging incessancy. Though some virtues wane, will others supply perfect completeness in my universe. Are we not a pair, born of heat and toil, controvertible, not better nor worse. Though shoulders may be cold or blood may boil, you are balanced and never violated. Timeless compass of perfect reckoning, northern star of mislaid paths translated, you, the first, though a second, beckoning Nature, forever, through her laws eschew dw + dq is dU 献给第一定律的十四行诗 Now let’s get some items, which you meet very often, into in English. pay attention to the English definition for the items! System and surrounding system: any portion of space or matter set aside for study. Open system: both matter and energy exchanges are involved Closed system: energy exchange with the surroundings is involved, but no matter exchange Isolated system: no matter or energy exchange with the surroundings is involved Surrounding: everything else, the universe outside the system Open system: water Closed system: water+container Isolated system : water+ container + surrounding air Heat and work energy transferred between system and surroundings is divided into two categories: Heat (Q): the energy changed because of the different temperatures Work (W) :all other forms of energy Algebraic sign of heat and work: Reversible and irreversible possesses whether the process of turning the initial state to the finial state is an infinite way, or not. Names for the energy Kinetic energy Potential energy Internal en