equilibria

• What type of reactions are reversible?

  Reactions where products can reform reactants
• How is a reversible reaction represented?

  Using a double arrow

  
• What characterizes the two reactions in a reversible system?

  One is endothermic, the other exothermic
• What is dynamic equilibrium in reversible reactions?

  Forward and backward reaction rates are equal
• What happens to concentrations at dynamic equilibrium?

  Concentrations of reactants and products are constant
• In what type of system does dynamic equilibrium occur?

  Closed systems
• What does Le Chatelier’s Principle predict?

  How equilibrium will change with altered conditions
• What does Le Chatelier’s Principle state about a system under change?

  The system will alter to lessen the change's effect
• How can Le Chatelier’s Principle be useful in industry?

  To maximize the yield of desired products
• What effect does increasing temperature have on endothermic reactions?

  It favors the endothermic reaction
• What happens when temperature is decreased in a reaction?

  It favors the exothermic reaction
• What is the sign of ∆H for endothermic reactions?

  Positive (+ve ∆H)
• What is the sign of ∆H for exothermic reactions?

  Negative (-ve ∆H)
• What effect does increasing pressure have on a reaction?

  It favors the side with fewer moles
• What happens when pressure is decreased in a reaction?

  It favors the side with more moles
• What effect does increasing the concentration of reactants have?

  It favors the production of products
• What happens when the concentration of products is decreased?

  It favors the reforming of reactants
• How do catalysts affect equilibrium position?

  Catalysts do not affect equilibrium position
• What do catalysts do to the rate of reaching equilibrium?

  They allow equilibrium to be reached faster
• What does Kc represent in reversible reactions?

  The position of equilibrium at a certain temperature

  
• When does the value of Kc change?

  When reaction conditions change
• How is Kc calculated?

  Concentration of products divided by reactants
• What happens to the number of moles in the Kc expression?

  Each substance is raised to the power of its moles
• How do the units of Kc vary?

  They depend on the chemical reaction
• What does changing temperature do to Kc?

  It affects the value of Kc
• What does changing concentration do to Kc?

  It does not affect the value of Kc
• How does a catalyst affect Kc?

  A catalyst does not affect the value of Kc