b) The units of entropy are Joules per degree Kelvin(/K). The units for specific entropy are c) For a system, ds T, where the numerator is the heat given to the system and the denominator is the temperature of the system at the location where the heat is received d)ds=0 for pure work transfer Muddy points Why is_dU= TdS-Pdvalways true?(MP 1B.1 What makes dOre, _ different than dO?(MP 1B.2) 1B.2 Axiomatic Statements of the Laws of Thermodynamics- (i. Introduction As a further aid in familiarization with the second law of thermodynamics and the idea of entropy, we draw an analogy with statements made previously concerning quantities that are closer to experience. In particular, we wish to(re-)present the Zeroth and First laws of thermodynamics in the same framework as we have used for the second law In this so-called"axiomatic formulation" the zeroth first and second laws are all introduced in a similar fashion (ii. Zeroth Law We start with a statement which is based on two observations a) If two bodies are in contact through a thermally-conducting boundary for a sufficiently long time, no further observable changes take place; thermal equilibrium is said to prevail b) Two systems which are individually in thermal equilibrium with a third are in thermal equilibrium with each other; all three systems have the same value of the property called mperature The closely connected ideas of temperature and thermal equilibrium are formally expressed in the Zeroth Law of Thermodynamics Zeroth llaw There exists for every thermodynamic system in equilibrium a property called temperature. Equality of temperature is a necessary and sufficient condition for thermal equilibrium The Zeroth law thus defines a property (temperature)and describes its behavior. Giii.)First Law Observations also show that for any system there is a property called the energy. The First Law asserts that one must associate such a property with every system First law There exists for every thermodynamic system a property called the energy ge of energy of a system is equal to the mechanical work done on the system in an adiabatic process. In a non-adiabatic process, the change in energy is equal to the heat added to the system minus the mechanical work done by the system From notes of Professor F. E C. Culick, California Institute of Technology(with minor changes) 1B-3b) The units of entropy are Joules per degree Kelvin (J/K). The units for specific entropy are J/K-kg. dQ c) For a system, dS = rev , where the numerator is the heat given to the system and the T denominator is the temperature of the system at the location where the heat is received. d) dS = 0 for pure work transfer. Muddy points Why is dU = TdS − PdV always true? (MP 1B.1) What makes dQrev different than dQ? (MP 1B.2) 1.B.2 Axiomatic Statements of the Laws of Thermodynamics 1 (i.) Introduction As a further aid in familiarization with the second law of thermodynamics and the idea of entropy, we draw an analogy with statements made previously concerning quantities that are closer to experience. In particular, we wish to (re-) present the Zeroth and First Laws of thermodynamics in the same framework as we have used for the Second Law. In this so-called "axiomatic formulation", the Zeroth, First and Second Laws are all introduced in a similar fashion. (ii.) Zeroth Law We start with a statement which is based on two observations: a) If two bodies are in contact through a thermally-conducting boundary for a sufficiently long time, no further observable changes take place; thermal equilibrium is said to prevail. b) Two systems which are individually in thermal equilibrium with a third are in thermal equilibrium with each other; all three systems have the same value of the property called temperature. The closely connected ideas of temperature and thermal equilibrium are formally expressed in the “Zeroth Law of Thermodynamics”: Zeroth Law There exists for every thermodynamic system in equilibrium a property called temperature. Equality of temperature is a necessary and sufficient condition for thermal equilibrium. The Zeroth law thus defines a property (temperature) and describes its behavior. (iii.) First Law Observations also show that for any system there is a property called the energy. The First Law asserts that one must associate such a property with every system. First Law There exists for every thermodynamic system a property called the energy. The change of energy of a system is equal to the mechanical work done on the system in an adiabatic process. In a non-adiabatic process, the change in energy is equal to the heat added to the system minus the mechanical work done by the system. 1 From notes of Professor F. E. C. Culick, California Institute of Technology (with minor changes) 1B-3