Exam 4

Exam 4

1. Chapter 14

   • Thermodynamics
     • Thermodynamics is about the transfer of energy between systems of particles
   • Temperature and Heat
     • Assume each system has its own temperature and T 1 > T 2 • System 1 is “ hotter ” than system 2
       • If the systems are brought into contact, energy is transferred spontaneously from system 1 to system 2
         • Eventually, the two systems will have the same temperature
     • The energy that flows between the systems is called heat or heat energy
       • A unit called the calorie is widely used for heat
         • 1 cal = 4.186 J
   • Phases of Matter
     • Solids
       • Arranged in an orderly and repeating pattern called a crystalline lattice
     • Liquids
       • Atoms are not held in fixed locations
     • Gases
       • The density of a gas is generally much lower than that of a liquid

2. Chapter 15

   • Avogadro’s number, N A is 6.02 x 10^23
   • m = (M/Na)
   • Avogadro's Law
     • For a sample of gas at constant pressure and temperature, the volume is proportional to the number of molecules in the sample
   • Boyle’s Law
     • For a sample of gas at constant temperature, the product of the pressure and volume is constant
   • Charles’ Law
     • For a sample of gas at constant pressure, if the temperature changes by a small amount Δ T, the volume changes by an amount Δ V, with Δ V ∝ Δ T

3. Chapter 16

   • U = (3/2)PV or U = (3/2)nRT
   • First law statement: If an amount of heat Q flows into a system from its environment and an amount of work W is done by the system on its environment, the internal energy of the system changes by an amount
     • Δ U = U f –U i = Q -W
   • If F is the force exerted by the gas on the piston, the work done by the gas on the piston is W = F Δ x
   • The work is W = P A Δ x = P Δ V
   • Isothermal Process
     • W = nRT ln(Vf/Vi)
   • Isochoric Process
     • W = P Δ V = 0