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 Assumpt ions:  There are many molecules moving in random direct ions at a variet y of speeds.  The molecules are, on average, far apart from each ot her. Their separat ion >> t heir diamet er.  Molecules obey classical mechanics laws regarding collisions, energy et c. And t hey int eract only t hrough collision, not t hrough at t ract ive forces (PE).  Collisions wit h ot her molecules or t he cont ainer wall are perfect ly elast ic. Time of collision << t ime bet ween collisions. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Equations:  pV = nRT  pV = nkT  PV/ T = const.  Boyle’s Law (V , P), Charles’ Law (V , T), Gay- Lussac’s Law (P , T).  KE = 3/ 2 kT = ½ mv 2  V rms = 3kT/ m Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Linear Expansion:  Volume Expansion:  Y ou’ re having trouble opening a glass j ar, how can you make it easier? Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Linear Expansion:  Volume Expansion:  Y ou’ re having trouble opening a glass j ar, how can you make it easier? Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

AP Physics B Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Density, pressure, volume… Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Two systems are said to be in thermal equilibrium if there is no net flow of heat between them when they are brought into thermal contact. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Two systems individually in thermal equilibrium with a third system are in thermal equilibrium with each other. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Change in internal energy of a system is equal to the heat transferred to/ from the system plus the work done on/ by the system: ΔU = Q + W  Comes from the law of conservation of energy.  S ign convention: heat energy Q/ W is positive when the system gains heat and negative when the system loses heat. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

S uppose you had a piston filled with a specific amount of gas. As you add heat, the temperature rises and thus the volume of the gas expands. The gas then applies a force on the piston wall pushing it a specific displacement. Thus it can be said that a gas can do WORK. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

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Jogging along the beach one day you do 4.3 x 10 5 J of work and a) give off 3.8 x 10 5 J of heat. What is the change in your internal energy? witching over to walking, you give off 1.2 x 10 5 J of heat and S b) your internal energy decreases by 2.6 x 10 5 J. How much work have you done while walking? Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

S ketch a PV diagram and find the work done by the gas during the following stages. (a) A gas is expanded from a volume of 1.0 L to 3.0 L at a constant pressure of 3.0 atm. (b) The gas is then cooled at a constant volume until the pressure falls to 2.0 atm Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

The gas is then c) compressed at a constant pressure of 2.0 atm from a volume of 3.0 L to 1.0 L. The gas is then heated d) until its pressure increases from 2.0 atm to 3.0 atm at a constant volume. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

What is the NET WORK? Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Internal Energy is a funct ion of st at e – it depends only on the state of a system, not on the method by which the system arrives at a given state  Quasi-static – a process that occurs slowly enough that a uniform pressure and temperature exist throughout all regions of the system at all times. There is no friction nor dissipative Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

To keep the temperature constant both the pressure and volume change to compensate. (Volume goes up, pressure goes down) “ BOYLES ’ LAW” Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

Heat is added to the gas which increases the Internal Energy (U) Work is done by the gas as it changes in volume. The path of an isobaric process is a horizontal line called an isobar. ∆U = Q - W can be used since the WORK is NEGATIVE in this case Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

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ADIABATIC- (GREEK- adiabatos- "impassable") In other words, NO HEAT can leave or enter the system. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

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 Example  A gas expands from an init ial volume of 0.40 m 3 t o a final volume of 0.62 m 3 as t he pressure increases linearly from 110 kPa t o 230 kPa. Find t he work done by t he gas. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Heat will only flow spontaneously from a body of higher temperature to a body of lower temperature.  For the reverse to happen, work must be done.  Example? Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

 Disorder in the universe can only increase. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

Heat flows from a HOT reservoir to a COLD reservoir Q H = remove from, absorbs = hot Q C = exhausts to, expels = cold Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

In order to determine the thermal efficiency of an engine you have to look at how much ENERGY you get OUT vs how much you energy you take IN. Eff. = W out = 1 - Q out Q in Q in Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

A heat engine with an efficiency of 24.0% performs 1250 J of work. Find (a) the heat absorbed from the hot reservoir, and (b) the heat given off to the cold reservoir. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

S ometimes it is useful to express the energy usage of an engine as a RA TE . For example: Q H t The RATE at which heat is absorbed! Q C The RATE at which heat is expelled. t The RATE at which WORK is DONE W  POWER t Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)

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Our goal is to figure out just how efficient such a heat engine can be: what’s the most work we can possibly get for a given amount of fuel? The efficiency question was first posed—and solved—by Sadi Carnot in 1820, not long after steam engines had become efficient enough to begin replacing water wheels, at that time the main power sources for industry. Not surprisingly, perhaps, Carnot visualized the heat engine as a kind of water wheel in which heat (the “fluid”) dropped from a high temperature to a low temperature , losing “potential energy” which the engine turned into work done, just like a water wheel. Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com)