Ch. 14, 15, 16

Ch. 14, 15, 16

1. Temperature and Heat

   • Heat Flow: transfer of energy from one object to another by temperature difference.
   • Heat Energy: Q=mc(delta)T
     • m=moles c=specific heat Q=heat energy
     • Heat measured in Joules (J)
       • Calorie is often used. 1 cal = 4.186 Joules
   • Calorimetry: We can find specific heat by adding a known amount of heat energy, Q, and measuring the resulting temperature change.
   • Zeroth Law of Thermodynamics: If systems A & B are in equilibrium, and systems B & C are in equilibrium, then systems A & C are too.
     • temperature is a unique property of a system that determines when 2 systems are in thermal equilibrium.
       • 3 Temp. Scales: Fahrenheit, Celsius, Kelvin
         • TK = TC + 273.15
         • TF = 9/5TC + 32

2. Gases and Kinetics

   • Kinetic Theory: The application of Newton's Laws to the mechanics of a gas of particles.
     • Ideal Gas Law: PV = nRT
       • R (ideal gas constant) = 8.32 J/mol K
       • Also be written as: PV = NkBT
         • kB (Boltzman's Constant) = 1.38 x 10^-23 J/K
   • Temperature of a dilute gas is equal to average KE of molecules. KE = 3/2 kB T
     • Internal Energy of a monatomic gas is equal to the total KE of the molecules. U= 3/2NkBT
   • Gas Laws
     • Avogadro's: At constant P and T, V is proportional to # of molecules.
     • Boyle's: Gas at constant Temp. = product of pressure and volume is constant. PV = constant
     • Charle's Law: Gas at constant Pressure, if temp. changes volume changes.
     • Gay-Lussac's Law: Gas at constant volume, pressure change is proportional to temp. change.

3. First Law of Thermodynamics: If amount of Heat, Q, flows into a system and amount of work, W, is done by the system on its environment, then the internal energy of system changes. (delta)U = Q - W

   • Second Law of Thermodynamics: Heat flows spontaneously from warm object to colder object. Heat cannot flow from cold to warm.
   • Third Law of Thermodynamics: It's impossible for the temperature of a system to reach absolute zero.
   • Q < 0 heat out of system. Q > 0 heat into system. W > 0 system does positive work on environment. W < 0 system does negative work on environment.
     • W = P(delta)V
     • Isothermic Process (Temp. Constant) : W = nRT ln(Vf/Vi)
     • Isobaric Process (Pressure Constant) : W = P(Vf - Vi)