GENCHEM 2 PART 1

• Spontaneous process


  A process that does not need the application of energy to take place
• Nonspontaneous process


  A process that cannot proceed unless there is a driving force or outside help that acts on the system
• Nonspontaneous process


  • A ball cannot be brought uphill unless someone pushes it
• Spontaneity of a process

  Determined from the change in entropy and change in free energy of a system
• Driving force for a spontaneous process

  Increase in the entropy of the universe
• Entropy (S)


  A measure of randomness or disorder
• Nature spontaneously proceeds toward the states that have the most "spread out energy", or the highest probabilities of existing
• Creating a mess is a more natural and spontaneous process than arranging or organizing things
• Factors that influence the amount of entropy present in a system

  • Change in Phase
  • Change in Temperature
  • Number of particles
• Change in Phase


  Solid particles have low entropy, liquid particles have higher entropy, and gas particles have the highest entropy
• Change in Temperature


  Increasing temperature increases entropy, decreasing temperature decreases entropy
• Number of particles


  More particles result in higher entropy
• Second Law of Thermodynamics


  The natural processes proceed in the direction that maintains or increases the total entropy of the universe, and in any spontaneous change, there is a net increase in entropy
• The second law of thermodynamics is one of the most powerful tools that helps explain everything in the physical world
• Equilibrium


  A state in which bodies in a system are neither in a state of motion nor in their internal energy state tends to change with time
• Chemical Equilibrium


  A state in which the rate of the forward reaction equals the rate of the backward reaction, resulting in no net change in concentrations of reactants and products
• Spontaneous process


  A process that does not need the application of energy to take place
• Nonspontaneous process


  A process that cannot proceed unless there is a driving force or outside help that acts on the system
• Reversible reaction


  Reactants are not completely converted into products, and some of the products may be converted back into reactants
• Nonspontaneous process


  • A ball cannot be brought uphill unless someone pushes it
• Irreversible reaction

  Represented by a single-headed arrow, indicating that the forward reaction is the only one occurring
• Reversible reaction


  Represented by a double-headed arrow, indicating that the forward and backward reactions are occurring simultaneously
• Entropy (S)


  A measure of randomness or disorder
• Reversible reaction


  aA + bB ⇌ cC + dD
• Nature spontaneously proceeds toward the states that have the most "spread out energy", or the highest probabilities of existing
• In a state of chemical equilibrium, the concentrations of the reactants and products become constant
• Creating a mess is a more natural and spontaneous process than arranging or organizing things
• The state of chemical equilibrium is a highly dynamic state, with the particles continuously reacting
• Law of Mass Action Expression/Equilibrium Constant Expression

  The relationship between the concentrations of the reactants and products, expressed as [C]^c[D]^d / [A]^a[B]^b = Keq
• Change in Phase


  Solid particles have low entropy, liquid particles have higher entropy, and gas particles have the highest entropy
• For heterogeneous equilibria, pure solids and pure liquids are excluded in writing equilibrium constant expressions
• Change in Temperature


  Increasing temperature increases entropy, decreasing temperature decreases entropy
• Equilibrium Constant (K)


  The numerical value obtained when equilibrium concentrations are substituted into the equilibrium constant expression, providing an idea of the relative concentrations of the reactants and products
• Number of particles


  More particles result in higher entropy
• In a state of chemical equilibrium, the rate of product formation is equal to the rate of reactant reformation
• Second Law of Thermodynamics


  The natural processes proceed in the direction that maintains or increases the total entropy of the universe, and in any spontaneous change, there is a net increase in entropy
• Chemical equilibrium is a dynamic situation, with the forward and reverse processes continuing to take place even though there is no change in the relative concentrations of the reactants and products
• Chemical equilibrium is mathematically described by the Law of Mass Action
• Equilibrium


  A state in which bodies in a system are neither in a state of motion nor in their internal energy state tends to change with time
• Chemical Equilibrium


  A state in which the rate of the forward reaction equals the rate of the backward reaction, resulting in no net change in concentrations of reactants and products