Mr. Shields Learning Objectives - Unit 13 Regents Chemistry

Equilibrium, Reaction Rates and Thermodynamics

  • Be able to recognize examples of the three types of equilibrium (Phase/Solution/Chemical) and be able to give examples of each
  • Know that chemical equilibriums can be either homogeneous (all the same phase) or heterogeneous (different phases)
  • Be able to state Le Chateliers principle and explain how it is applied to explain a shift in equilibrium
  • Be able to state the stress on the system and the System response to the stress
  • Be able to recognize or draw curves describing how rates and concentration behave as a function of time as they approach equilibrium
  • Know that at equilibrium the rate of the forward and reverse reactionsare equal ( RateF = RateR )
  • Being in Equilibrium does not require the Concentration of Reactant and Products to be the same (equal), just constant (unchanging)
  • Be able to use the head to tail method to describe in what direction a stress will shift an equilibrium
  • Can only be used for changes in concentration or temp (Not Pressure!)
  • Be able to describe how a change in temperature, concentration or Pressure affects the direction of an equilibrium
  • After stressing the system by changing one of these values be able to describe how the other reactants, products and energy change
  • Know that pressure only affects equilibriums in which some of the reactants and/or products are in the gaseous state
  • Based on the # of moles of reactants and products be able to predict which direction a reaction will shift when increasing or decreasing the pressure on the system
  • Any component that is not a gas counts as 0 (zero) moles
  • Know that shifting an equilibrium in one direction means increasing the rate of reaction in that direction
  • Be able to recognize the Haber Process for the production of ammonia and be able to describe how the yield of ammonia can be optimized (increased) by changing conditions of the reaction
  • Know that the rate of reaction means the change in concentration of reactants to products per unit time
  • Using collision theory describe how chemical reactions occur in terms of 1) collision, 2) proper orientation, 3) Sufficient Kinetic Energy.
  • If all three are met the collision is an effective collision leading to product
  • Understand and be able to explain why Nature of reactants, Temperature, concentration, surface area and catalysts affect reaction rate.
  • When considering the nature of reactants be able to predict, when presented with several choices, which reaction or compound will react faster than the others
  • ionic reaction rates (ions)> inorganic rates (ionic bonds).> organic rates (covalent bonds)
  • Know gaseous reactions > Liquid reactions > solid reactions
  • Be able to recognize and explain the differences between an effective and ineffective collisions
  • Describe the term “two body” collision and how it pertains to Collision theory
  • Be able to describe Activation Energy (EA) and the properties of the activated complex
  • Be able to describe on a molecular scale how a catalyst works to speed up reaction rates
  • Catalysts speed up the reaction rates of the forward and reverse reaction equally
  • Be able to draw a PE curve showing the effect of a catalyst on the energy of activation
  • Know that a catalyst is never consumed, i.e. it does not become incorporated into product
  • Catalysts are usually designated by writing them over the reaction arrow(s)
  • Know that a catalyst decreases the time to reach equilibrium but does not change the final equilibrium concentrations or final rates of the forward and reverse reaction
  • Be able to explain the terms Enthalpy, Entropy, Spontaneous reaction, endothermic and exothermic reactions
  • Know that a reaction is exothermicif the enthalpy is negative (-H) and endothermicif it is positive (+H)
  • Know that very exothermic reactions (-H) tend to be spontaneous
  • Know that H (enthalpy) is also known as the Heat of Reaction
  • In exothermic reactions products are more stable than reactants but vice versa for endothermic reactions
  • Be able to draw and label a PE curve for an exothermic and endothermic reactions and be able to indicate whether reactants or Products have greater PE
  • Given a specific PE curve be able to calculate H, Activation Energy, PE of products, PE of reactants, and the energy of the activated complex.
  • H = Hproducts - Hreactant (This must be written in this sequence; it defines the sign of H)
  • Know what factors increases or decrease entropy
  • S = Sproducts - Sreactant
  • Know that Entropy is a measure of system disorder
  • +S means Products have more disorder
  • -S mean reactants have more disorder
  • Know that the more positive theS term the more the system moves to disorder and that systems like to become more disordered
  • Know that +S favors spontaneous reactions
  • Given a set of reactants and products be able to state whether Entropy is increasing or decreasing when going from reactant to product
  • Know that Enthalpy and Entropy together determine whether a reaction will be spontaneous
  • When the following is true ( -H and +S ) the reaction is definitely spontaneous
  • When the following is true ( +H and -S ) the reaction is definitely NOT spontaneous

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