# Thermodynamics II Pt 2

 Constant-Pressure process (or ______ process) (______' law): Pi = ___ What does this mean for final and initial volume/temperature Isobaric processCharles' law With a fixed piston, the system is in _______, pressure must be the same on both sides of the piston With a movable piston, because the external pressure doesn't change, the gas pressure remains ________ as the gas expands  An isobaric process appears on a pV diagram as a ________ line equilibrium constant horizontal line An isobaric process is one that occurs at a _______ _______. The values of the heat and the work are generally both _______ values.  W = ____ = _______ p is the ______ ______ From the First Law:  ΔEth = ___ + ___ = ___ - _____ constant pressurenonzeroW = -Wgas = -p(Vf - Vi)constant pressureΔEth = Q + W = Q - p(Vf - Vi) Constant-Volume or ________ Process (________'s law):  Vi = ___ pi/Ti = ___ As the temperature increases, the pressure __________ A constant-volume process appears on a pV diagram as a _______ ______ IsochoricGuy-Lussac's lawVi = Vfpi/Ti = pf/Tfincreasesvertical line Isochoric Process An ________ process is one in which there is no change in the volume  ΔV = ___ ⇒ W = ____ From the First Law: ΔEth = ____ isovolumic process0 0Q Isochoric process If energy is added by heat to a system kept at constant volume, all of the transferred energy remains in the system as an increase in its _______ ______ internal energy Constant-Temperature Process (or _______ process) are under _______'s law:  Ti = ___ piVi = _____, making it ______ Isothermal processBoyle's law TfpfVf, making it constant An isothermal process appears on a pV diagram as a _______ hyperbola An ________ process is one that occurs at a constant temperature. Since there is no change in temperature, ΔEth = ___ From the First Law:  Q = ___ Any energy that enters the system as heat must leave the system by _____ isothermal process0-Wwork The graph of an isothermal process is known as an _______. Different temperatures correspond to different ________ isothermisotherms What is the formula for work done on a ideal gas in an isothermal process?  Define adiabatic process and state its first law Adiabatic process: a process during which no energy enters or leaves the system by heat, Q = 0First Law: ΔEth = Q + W = W The curve of the adiabatic compression moves from a _______ ________ isotherm to a ______ _______ isotherm lower temperature isothermhigher temperature isotherm An adiabatic process is one under which  no ______ enters or leaves the system, in other words, no _____ is exchanged with the environment. State two ways this is achieved and give an example heatheatThermally insulating the walls of the systemHaving the process proceed so quickly that no heat can be exchangedExample: rapidly expanding gas which drops its pressure precipitously and simultaneously cools. This is the principle in a snow-making machine Free expansion is a unique _______ process. _____ work is done on the gas, W = ___. Since Q = ____ and W = ____, ΔEth = ____ adiabatic processNo work W = 0Q = 0 and W = 0 ΔEth = 0 In Free expansion, the ______ and ______ energies are the same, and no change in ________ is expected initial and final energiestemperature A ______ process is one that originates and ends at the same state. This process would not be _______ and on a PV diagram, it appears as a _______ ______. cyclic processisolatedclosed curve In a cyclic process, the energy added by heat to the system must therefore equal the ________ of the work done on the system during the cycle  ΔEint = ____ and Q = ____ The net work done per cycle  = ? negative 0 -WThe net work done per cycle equals the area enclosed by the path on a PV diagram Summarize the Q,W and ΔEth different types of processes ΔEth = Q+W (6)  A. B. solve for T, we know p, V and n is constant B. A. N = 8 * 1026 atoms of air Power = 50 WDuration = 10 min (energy goes to air particles)p(power)Δt(time) = energy = ΔEth (so this is neither of the 6 processes) ΔEth = 3/2nR(Tf - Ti) *for monatomic gasair is mostly Nitrogen which is diatomic so:ΔEth = 5/2nR(Tf - Ti) pΔt = 5/2nRΔT = 5/2NKBΔTΔT = 1.09 C see slides then notes Define energy reservoir Energy reservoir: an object or part of the environment whose temperature does not noticeably change when heat is transferred between the system and itself Differentiate between a hot and cold reservoir as well as QH and QC (what do the Qs have in common?)  Heat is never spontaneously transferred from a _____ object to a ______ object colderhotter A heat engine is a device that is able to take energy from a _____ reservoir, transform some into useful _____, and deposit the rest as ______ energy in a ______ reservoir. hotworkthermal energycold Label the heat engine Assume there is no net energy transfer into or out of the heat engine. Thus,  QH = ____ + _____ All quantities are ______ QH = QC + Woutpositive What is the efficiency formula for a heat engine (3) QH is what you had to pay (why?) No heat engine can operate without exhausting some fraction of the heat into a _____ _______. It is a fundamental law of matter.  What is the formula for maximum efficiency (or ______ efficiency) of any heat engine  What is the units for temperature because this is the energy of the fuel burnedcold reservoirCarnot efficiency  emax = 1 - (TC/TH)A. emax = 1 - (303.15/573.15) = .47108B. emax = 1 - (303.15/523.15) = .4205C. emax = 1 - (293.15/473.15) = .3804 D. emax = 1 - (283.15/373.15) = .2412E. emax = 1 - (273.15/363.15) = .2478ans = A. emax = 1 - (TC/TH)emax = 1 - (288.15/513.15) = .4385 What is the job of a heat pump? Since it is a process against the natural direction, what happens to the system? Thus, QH = ? All quantities are ______ To transfer heat energy from a cold reservoir to a hot reservoirwork is done to the system QH = QC + Win positive Label the heat pump  You can use the heat pump for cooling, e.g. a ________. The ________ _____ _________ (____) is a quantity similar to the efficiency of the heat engine. refrigeratorCoefficient of Performance (COP) State the formula for COP (3) and Maximum COP of a heat pump used for cooling What units must temperature be in? You can use the heat pump for heating, state an example State the formula for both COP (3) and the formula for Maximum COP of a heat pump used for HEATING State the units for temperature warming a winter cabin Larger COP means a more _______ heat pump! Unlike the efficiency of heat engine (e<1), COP of heat pump can be _______ than 1 efficient greater COP = Qc/WinCOPmax = TC/(TH-TC) B. 1 & 4 Label the heat engine (11-story) **The available arrows are just hints and not all of the actual arrows State 4 important characteristics of this heat engine (previous card)  Define entropy Natural processes tend to move toward a state of _______ ________. Only _______ energy has entropy Entropy: a measure of the order or disorder of a systemgreater disorderthermal energy The ordered, organized motion of the baseball (macroscopic _______ energy) has _____ entropy, while the disorganized random motion of the gas atoms (_______ energy) in a balloon has _____ entropy.  State-wise: Entropy of _____ < Entropy of ______ < Entropy of ______ kinetic low thermal high Entropy of solid < Entropy of liquid < Entropy of gases For a baseball and a balloon, state the the direction and speed of motion of the molecules, the type of motion, and the type of energy Authorchikeokjr ID344555 Card SetThermodynamics II Pt 2 DescriptionThermodynamics II Pt 2 Updated2019-01-22T18:25:28Z Show Answers