热力学导论第2章question和problem答案.pptVIP

2-1.Please explain the following thermodynamic terms: ;3). state functions(p.2-5, L.13-17); Answer:These properties do not depend on the past history of the substance or on the path it has before or on the path it has followed in reaching a given state.They depend only on the present conditions. 4).critical point(p.3-1, L.9-11); Answer: The coordinates of this point are called the critical pressure Pc and the critical temperature Tc.These represent the highest temperature and temperature at which a pure material can exist in vapor-liquid equilibrium.Homogeneous fluids are normally divided into two classes, liquids and gases. However, the distinction cannot always be sharply drawn, because the two phases become indistinguishable at what is called the critical point .;5).ideal gas(p.3-8, para2,L6-10); Answer: Their actual volume becomes infinitesimal compared with the total volume cccupied by the gas,and the intermolecular forces of attraction approach zero.A gas which meets these conditions is known as an ideal gas. 6).compressibility factor(p.3-9, L.11).Answer: The ration PV/RT is called the compressibility factor ;2-2 Give the statement and formulation of the first law of thermodynamics(P2-2,L25-26);2-3 What is the difference between the state function and work or heat?(p2-5,2-6);3.The differential of a state function is spoken of that as an infinitesimal chang in the property,and is not referred to as a quantity.The differentials of heat and work are not referred to as changes, but are regarded as infinitesimal quantities of heat and work. 4.Another difference between state functions and heat or work follows from the fact that a state function represents an instantaneous (瞬间的) property of a system and always has a value (有一确定值). Work and heat appear only when changes are caused in a system by a process, which requires time.;2-4.What are the necessary conditions for the steady state flow process?(p.2-12)  Answer: The term steady state implies that condition