Concept Map 4

Concept Map 4

1. Chapter 14

   • Thermodynamics:
     • Thermodynamics focuses on energy rather than forces.
       • Conservation of energy is a key pillar of thermodynamics.
         • Quantities such as temperature and heat are needed for properties of system interactions.
           • A system contains multiple particles, usually a very large amount.
             • Systems are able to exchange energy with other systems.
               • A balloon filled with oxygen is an example of a system.
                 • In comparing tow systems, they may not be identical on the molecular level.
                   • Various properties of the system as a whole will be the same
                     • System wide properties include temperature and pressure.
                       • We are generally interested in the macroscopic properties of the system.
                         • They describe the behavior of the system o a scale much larger than the individual particles.
                         • Macroscopic and microscopic properties of the system are connected.
   • Temperature:
     • Temperature is not contained in nor derivable from Newton's laws.
       • Heat flows from hot to cold.
         • Thot > Tcold
         • Temperature is connected with the terms "hotness" or "coldness".
           • Eventually two interacting systems will have the same temperature.
             • They will reach a thermal equilibrium.
             • The energy that flows between the systems is called heat or heat energy.
               • Heat is energy that passes from one system to another by virtue of a temperature difference.
                 • Heat = Energy
                   • According to the principle of conservation of energy the heat energy that leaves system 1 must equal the amount that enters system 2.
                     • The direction of the transfer depends only on the temperature difference.
                       • UNITS OF HEAT:
                         • SI unit of heat is the same as energy. Joule (J).
                         • A unit called the calorie is widely used for heat. 1 cal = 4.186 J
                         • Calorie with uppercase C is used in food. 1 Calorie = 1000 calories.
                         • Three temperature scales that are common today:
                           • Celcius
                             • Water freezes at 0 degrees.
                               • Water boils at 100 degrees.
                           • Fahrenheit
                             • Water freezes at 32 degrees.
                               • Water boils at 212 degrees.
                           • Kelvin
                             • Water freezes at 273.15 K
                               • Water boils at 373.15 K
                                 • No degree symbol is used.
                           • Temperature Conversions:
                             • TK = TC + 273.15
                             • Tf = 9/5Tc + 32
                             • 0th Law.

2. Chapter 15

   • Gases and Kinetic Theory
     • Newton's Laws are used to analyze the behaviors of gas
     • Dilute gases can lead to connections between temperature and motion on an atomic scale
     • Ideal gas notion "kinetic theory"
       • Apply to dilute gases
     • Atomic mass (M) in (g) is the mass of one atom. m=M/N
       • N= Avogadro's number
     • Gases
       • Collide with other gas molecules and walls of their container
       • Molecules are in constant motion
       • Molecules move in all directions and with different speeds
     • Avagadro's Number: N= 6.02 x 10^23
       • Connects microscopic world to macroscopic world
       • Number of particles in 1 mole
     • Avogadro's Law
       • Gas at a constant pressure and temperature. Volume is proportional to the number of molecules in sample
         • V proportional to N
     • Charle's Law
       • Gas at constant pressure. If temperature changes slightly the volume changes by a small amount
       • V is proportional to T
     • Boyle's Law
       • Gas at constant temperature. Product of pressure and volume is constant.
       • PV= constant
       • P proportional to 1/V
     • Gay-Lussac's Law
       • Gas held in container with constant volume, changes in pressure are proportional to changes in temperature
         • P proportional T
       • Involved with gas thermometers
     • Ideal Gas Law
       • PV= nRT
       • R= 8.31 J/mole K
       • n= # of moles of gas present
       • Ideal Gas Law represented with number of particles. PV=(N/Na)RT= N(R/Na) T
         • R/Na is Boltzmann's Constant (kB)
           • kB=1.38x10^23
       • PV= N kB T
     • Elastic Collisions: The speed before and after will be the same.
       • P=Nmv^2/3V and PV=N (mv^2/3)
     • Kinetic Energy: 3/2 kB T
     • Molecular Speeds: v=sqrt of 3 kB T/m
     • Specific Heat of Ideal Gas
       • Heat energy added to ideal gas will cause increase in both KE and internal energy (U)
   • Internal Energy: Mechanical energy of a particle in an ideal gas is equal to its KE
     • Internal Energy depends only on the number of particles present and the temperature of the gas
     • In terms of the number of moles: U=3/2 n R T
     • Applies to monatomic gases
     • change U= change Q= 3/2 n Kb change in T

3. Chapter 16

   • The principles of thermodynamics are enshrined in 4 laws. Three are discussed
     • The Zeroth Law of Thermodynamics concerns the flow of heat
       • If System A and B are ine equilibrium with system C, then A and B are in equilibrium with each other
     • The First Law states that the change in internal energy of a system is equal to the heat flow Q into the system minus the work W done by the system on its environment
       • Change in U = Q - W
         • Work = P(Change in V) = 0 in an isochoric process
         • W = n RT ln(V(f)/V(i) in an isothermal process
         • W = P(Change in V) in an isobaric process
         • W = The area under the PV diagram in an adiabatic process
           • This is demonstrated on the graph below
       • Work is positive when a gas expands, and force is parallel to displacement; it is negative when a gas compresses, and force is anti-parallel to displacement.
       • U = (3/2) N x K(B) x T or (3/2) n R T
     • The Second Law states in simple terms that heat flows from a hot object to a colder one.
       • The Second Law also describes irreversible processes
         • In two reservoirs of different temperature, Q(c)/Q(h) = T(c)/T(h)
           • Efficiency = 1 - (T(c)/T(h)). This is the maximum efficiency of a heat engine.

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