1.6 Equilibria

• Equilibria are represented by the symbol ⍺.
• Reversible reactions involve going forward and backwards, represented by harpoons.
• In a reversible reaction, the forward reaction initially uses up the reactants quickly, but the backwards reaction reforms them slowly.
• Equilibrium is reached when the amount of reactant and product is the same, this is called dynamic equilibrium.
• In a reversible reaction, the concentration of each substance remains constant when it reaches equilibrium.
• Equilibrium only occurs in closed systems.
• Alicia Tilly and Attilio developed a principle stating that if a reaction equilibrium is subject to a change in pressure, temperature, or concentration, the position of the equilibrium will move to counteract that change.
• If a change in condition results in equilibrium shifting to the left, more reactants are made.
• If a change in condition results in equilibrium shifting to the right, more products are made.
• If 33.2 grams of NO2 are heated in a vessel with a volume of 9.65 decimeters cubes at 450 degrees Celsius, 6.8 grams of O2 are found in the equilibrium mixture.
• The concentration of O2 at equilibrium can be calculated using the formula: moles of O2 / volume of reaction vessel.
• Two moles of NO2 produce two moles of NO and oxygen.
• The units of KC are moles per diem cubed.
• The equilibrium concentrations of NO2 and O2 can be calculated using the KC value.
• The concentration of NO2 at equilibrium can be calculated using the formula: moles of NO2 / volume of reaction vessel.
• The equilibrium constant (KC) for the reaction can be calculated using the formula: products over reactants / oxygen divided by nitrogen dioxide.
• Nitrogen dioxide decomposes according to the reaction:
• The compromise between yields and rate is achieved at a temperature of 300 degrees Celsius.
• If the temperature is decreased, equilibrium shifts to the right and more ethanol is produced.
• The conditions of the reaction are: pressure 60 atmospheres, temperature 300 degrees Celsius, catalyst phosphoric acid, and the forward reaction is exothermic.
• Increasing the pressure in the reaction increases the rate, but it also increases the cost due to the need for thicker, more robust pipes and containers.
• The units for KC can vary depending on the concentrations used in the calculation.
• The equilibrium constant (KC) is a value given to an equilibrium reaction, calculated from the molar concentration in a reaction.
• Catalysts speed up both the forward and reverse reactions equally, meaning they have no effect on yields.
• An increase in temperature will cause the equilibrium to shift in the endothermic direction, reducing the temperature and producing more products.
• If the temperature is decreased, the equilibrium will shift in the exothermic direction, increasing the temperature and producing more products.
• Catalysts have no effect on the position of equilibrium.
• If the concentration of reactants is increased, equilibrium will shift to the right to use up the reactants and produce more products.
• If the pressure is decreased, the equilibrium will shift to the side with the most number of gas particles, trying to increase the pressure and produce more reactants.
• If the concentration of products is increased, equilibrium will shift to the left to use up the products and produce more reactants.
• In a homogeneous equilibrium, an increase in pressure will cause the equilibrium to shift to the side with the fewest number of gas particles, reducing the pressure and producing more products.
• In a homogeneous equilibrium, reactants and products are in the same state.