Sub-topic #2: Stress

• Stress such as decreasing the concentration of one

  side of the chemical equation (either reactant or

  product side) will favor the formation of that side of

  the equation.
• While increasing the concentration will favor the

  formation of the opposite side.
• Temperature

  • Temperature causes a shift in equilibrium because all chemical changes involve either endothermic or exothermic energy.
• Endothermic – absorption of energy.
• Exothermic – release of energy
• Temperature

  • In a reversible reaction, a temperature increase can favor the reaction in the endothermic direction.
• Temperature

  • This is because it helps absorb the extra heat, balancing the system.
• Temperature

  • Only temperature can change the value of the equilibrium constant, as it is fixed at a specific temperature.
• Temperature

  • Equilibrium Constant – tells us the ratio of products to reactants at equilibrium.
• C and D – products

  
• A and B - reactants

  
• [C], [D], [A], [B] - concentrations of the chemicals involved

  
• c, d, a, b - coefficients from the balanced

  chemical equation

  
• K > 1 – reaction favors the products.

  
• K < 1 - reaction favors the reactants

  
• K – constant at a given temperature, but

  changes if the temperature changes

  
• Pressure and Volume

  • Change in pressure or volume affects only gaseous species.
• Pressure and Volume

  • Increase in pressure (decrease in volume) will favor the reaction to produce less gas molecules.