genchem Q4

• Spontaneous process- This type of process does not need the application of energy to take place is said to be spontaneous process
• nonspontaneous process - 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 - can be determined from the change in entropy and change in free energy of a system. 
• The driving force for a spontaneous process - is an increase in the entropy of the universe.
• Entropy, S

  • as 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 organizing
• Change in Phase - Solid particles are confined to fixed positions or compactly arranged so that they can hardly move, thus, entropy is relatively low. 
• Change in Temperature -

   Increasing the temperature increases the entropy of a system while a decrease in temperature results in lowering of entropy.
• Number of Particles -  When a lot of people are present, there will be more movement, more noise, more wastes, and greater disorder.
• Second Law of Thermodynamics -  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.
• Second Law of Thermodynamics - this law is one of the most powerful tools that helps explain everything in the physical world. 
• Equilibrium, in Physics - occurs when bodies in a system are neither in a state of motion nor in their internal energy state tends to change with time. 
• Equilibrium in Economics - is the state in which market supply and demand balance each other, and as a result prices become stable
• Chemical equilibrium -  also called as dynamic equilibrium
• Chemical equilibrium -  is a state in which the rate of the forward reaction equals the rate of the backward reaction. 
• Reversible reactions - the reactants are not completely converted into products and some of the products may be converted back into reactants
• State of balance - is also referred to as a state of equilibrium
• Reversible reaction - when the reactants start to form the products, the products would then start to reform the reactants.
• Chemical Equilibrium -  there are no change in the composition of the reaction mixture and no visible changes taking place, the particles are continuously reacting.
• Chemical equilibrium can be easily disturbed by changes in the reaction conditions.
• The Law of Mass Action Expression - also known as  Equilibrium Constant Expression.
• The Law of Mass Action Expression - The relationship between the concentrations of the reactants and products may be expressed using this law.
• [] - symbol of concentration expressed in molarity
• Kc -  If molar concentrations are used, Keq may also be referred to as Kc
• The law of mass action - the ratio of the concentrations of the products raised to their respective stoichiometric coefficients to that of the reactant
• Equilibrium constants for homogeneous gaseous equilibria may also be expressed in terms of partial pressures
• Keq - the equilibrium constant. 
• Partial pressure is raised to the coefficient instead of the molar concentration.
• When the mass of a certain pure solid substance is doubled what happens to its volume ?

  • doubled
• The equilibrium constant, K -

   is the numerical value that is obtained when equilibrium concentrations are substituted to the equilibrium constant expression.  
• Equilibrium Constant, K -

   This value provides an idea of the relative concentrations of the reactants and products in an equilibrium mixture
• Equilibrium - It is a state of “balance” when the rate of product formation is equal to the rate of reactant reformation.
• If the number of moles of one component increases, then the equilibrium position moves away from this component. The opposite applies if there is a reduction in the number of moles of any component.
• Chemists Johannes Nicolaus Brønsted and Thomas Martin Lowry independently developed definitions of acids and bases


  1923
• Brønsted-Lowry acid


  Proton (hydrogen ion) donor
• Brønsted-Lowry base

  Proton (hydrogen ion) acceptor
• Amphoteric


  A compound that acts as both a Brønsted-Lowry acid and base together
• Brønsted-Lowry theory of acid and bases


  • Took the Arrhenius definition one step further, as a substance no longer needed to be composed of hydrogen (H+) or hydroxide (OH-) ions to be classified as an acid or base