Please enable JavaScript.

Coggle requires JavaScript to display documents.

Kinetics, CHEM 111 topics - Coggle Diagram

- - - - A=products
      - rate=k[A]
    - - 2NO+O2=2NO2
      - rate=k[NO]2[O2]
    - - A+B=products
        
        2A=products
      - rate=k[A][B]
    - - slowest step
- - - - not at equilibrium
    - - law of mass action
        
        When a reaction has attained equilibrium at a given temperature, the reaction quotient for the reaction always has the same value.
    - - is one in which all of the reactants and products are present in a single solution (by definition, a homogeneous mixture)
    - - a system in which reactants and products are found in two or more phases. The phases may be any combination of solid, liquid, or gas phases, and solutions.
  - - - increase pressure
        
        either by decreasing the volume of the system or by adding more of one of the components of the equilibrium mixture, we introduce a stress by increasing the partial pressures of one or more of the components.
      - change temp
        
        A change in temperature actually changes the value of the equilibrium constant.
        
        Increasing the temperature
        
        ncreases the internal energy of the system.
        
        increasing the amount of one of the products of this reaction.
        
        The reaction shifts to the left to relieve the stress,
        
        is an increase in the concentration of reactants
        
        1 more item...
        
        Lowering the temperature
        
        we put a stress on the system by cooling the mixture (withdrawing energy),
        
        equilibrium shifts to the left to supply some of the energy lost by cooling.
      - When a chemical system at equilibrium is disturbed, it returns to equilibrium by counteracting the disturbance. As described in the previous paragraph, the disturbance causes a change in Q; the reaction will shift to re-establish Q = K.
      - Catalysts Do Not Affect Equilibrium
        
        a catalyst can speed up the rate of a reaction
        
        may cause a system to reach equilibrium more quickly (by speeding up the forward and reverse reactions)
  - - - If concentrations of reactants and products at equilibrium are known, the value of the equilibrium constant for the reaction can be calculated.
    - - If the value of the equilibrium constant and all of the equilibrium concentrations, except one, are known, the remaining concentration can be calculated.
    - - If the value of the equilibrium constant and a set of concentrations of reactants and products that are not at equilibrium are known, the concentrations at equilibrium can be calculated.
      - step 1 Determine the direction the reaction proceeds to come to equilibrium.
        
        a) Write a balanced chemical equation for the reaction.
        
        b) If the direction in which the reaction must proceed to reach equilibrium is not obvious, calculate Qc from the initial concentrations and compare to Kc to determine the direction of change.
        
        step 2: Determine the relative changes needed to reach equilibrium, then write the equilibrium concentrations in terms of these changes.
        
        a. Define the changes in the initial concentrations that are needed for the reaction to reach equilibrium. Generally, we represent the smallest change with the symbol x and express the other changes in terms of the smallest change.
        
        b. Define missing equilibrium concentrations in terms of the initial concentrations and the changes in concentration determined in (a)
        
        step 3: Solve for the change and the equilibrium concentrations.
        
        a. Substitute the equilibrium concentrations into the expression for the equilibrium constant, solve for x, and check any assumptions used to find x.
        
        b. Calculate the equilibrium concentrations.
        
        step 4: Check the arithmetic.
        
        Sometimes a particular step may differ from problem to problem—it may be more complex in some problems and less complex in others. However, every calculation of equilibrium concentrations from a set of initial concentrations will involve these steps.
        
        In solving equilibrium problems that involve changes in concentration, sometimes it is convenient to set up an ICE table, as described in the previous section.
        
        1 more item...
  - - - strong acids/bases will dissociate
        
        pH and pOH calculation
        
        pH: logarithmic measure of the concentration of hydronium ions in a solution
        
        pOH: logarithmic measure of the concentration of hydroxide ions in a solution
      - weak acids/bases will not completely disacoiate
        
        pH calculation
        
        Kb
        
        equilibrium constant for the ionization of a weak base
        
        Ka
        
        equilibrium constant for the ionization of a weak acid
        
        Kw
        
        equilibrium constant for the autoionization of water
        
        ice box
    - - acidic: describes a solution in which [H3O+] > [OH−]. Basic describes a solution in which [H3O+] < [OH−]
      - color-change interval
        range in pH over which the color change of an indicator takes plac
    - - buffer capacity
        amount of an acid or base that can be added to a volume of a buffer solution before its pH changes significantly (usually by one pH unit)
    - - substance formed when a base gains a proton
    - - substance formed when an acid loses a proton
  - - - solubility product (Ksp)
        
        process in which ions are separated using differences in their solubility with a given precipitating reagent
        
        equilibrium constant for the dissolution of a slightly soluble electrolyte
      - Predicting Precipitation
        
        selective precipitation
        
        process in which ions are separated using differences in their solubility with a given precipitating reagent
      - common ion effect
        
        effect on equilibrium when a substance with an ion in common with the dissolved species is added to the solution; causes a decrease in the solubility of an ionic species, or a decrease in the ionization of a weak acid or base
      - molar solubility
        
        solubility of a compound expressed in units of moles per liter (mol/L)
    - - Kf
        
        (Kf) (also, stability constant) equilibrium constant for the formation of a complex ion from its components in solution
      - Kd
        
        (Kd) equilibrium constant for the decomposition of a complex ion into its components in solution
      - complex ion
        
        ion consisting of a transition metal central atom and surrounding molecules or ions called ligands
      - Lewis acid
        
        any species that can accept a pair of electrons and form a coordinate covalent bond
      - Lewis base
        
        any species that can donate a pair of electrons and form a coordinate covalent bond
      - Lewis acid-base adduct
        
        compound or ion that contains a coordinate covalent bond between a Lewis acid and a Lewis base
    - - system characterized by more than one state of balance between a slightly soluble ionic solid and an aqueous solution of ions working simultaneously
- - - - is one that occurs naturally under certain conditions
    - - will not take place unless it is “driven” by the continual input of energy from an external source.
  - - - refers to a process that takes place at such a slow rate that it is always at equilibrium and its direction can be changed (it can be “reversed”) by an infinitesimally small change is some condition.
    - - predicting ∆S
    - - microstate (W)
        
        is a specific configuration of the locations and energies of the atoms or molecules that comprise a system like the following
  - - - Standard entropies are given the label S∘298for values determined for one mole of substance at a pressure of 1 bar and a temperature of 298 K.
  - - - ∆G=∆H-T∆S
        
        helps predict spontanitey
        
        ∆H and ∆S can predict ∆G
        
        +∆H and +∆S
        
        ∆G wil be negatie and is spontaneous at high temperatures and nonspontaneous at low temperatures.
        
        -∆H and -∆S
        
        ∆G will be negative and is spontaneous at low temperatures and non-spontaneous at high temperatures
        
        +∆H and -∆S
        
        ∆G wil be positive and is is nonspontaneous at all temperatures.
        
        -∆H and +∆S
        
        ∆G will be negative spontaneous at all tematures