C8

• Effect of Reactant Availability on Reaction Rate

  The rate of reaction increases initially due to abundant reactants, slows down as reactants are consumed, and eventually ceases when reactants are depleted.
• Collision Theory


  A scientific model that explains the rate of reaction in terms of particle collisions, where the rate is influenced by the number of particles colliding and the energy of particles.
• Factors Affecting Reaction Rate

  The number of particles colliding and the energy of particles; any change in these factors can alter the rate of reaction.
• Effect of Temperature on Reaction Rate

  Increasing temperature increases molecular motion, resulting in more collisions per second and a faster reaction rate.
• Impact of Molecule Speed on Reaction Rate

  Fast-moving molecules are more likely to have sufficient energy for a successful reaction, while slow-moving molecules are less likely to react.
• Effect of Temperature on Reaction Rate

  As temperature increases, the rate of reaction increases due to increased molecular motion and collisions.
• Effect of Low Temperature on Reaction Rate

  At low temperatures, particles move slowly, leading to fewer collisions, insufficient energy for reaction, and a slow reaction rate.
• Effect of High Temperature on Reaction Rate

  At high temperatures, particles move faster, leading to more collisions, sufficient energy for reaction, and a faster reaction rate.
• Effect of Temperature Increase on Reaction Rate

  Increasing temperature increases the frequency of collisions and the energy of particles, resulting in a doubling of the reaction rate for every 100°C temperature increase.
• Effect of Solution Concentration on Reaction Rate

  Increasing the concentration of a reactant in solution increases the likelihood of collisions, resulting in a faster reaction rate. Concentration is measured in mol/dm3, which represents the number of moles of particles per cubic decimeter of solution.
• Definition of a Mole

  A mole (mol) represents 6.022 x 10^23 particles, while the molar mass is the mass of one mole of a substance in grams, obtained from the periodic table.
• Collision Theory of Reaction Rates in Solution

  Reactions in solution involve dissolved particles that must collide, and the more crowded the solution (higher concentration), the faster the reaction.
• Effect of Gas Pressure on Reaction Rate

  Increasing gas pressure results in more collisions and a faster reaction rate, as gases at the same pressure and temperature contain the same number of particles.
• How Catalysts Work


  Catalysts speed up reactions by lowering the activation energy, making particles more likely to collide and react.
• Catalysts and Activation Energy

  Catalysts reduce the activation energy needed to start a reaction, making it easier and faster, and also allow reactions to occur at lower temperatures, without being consumed in the process.
• Advantages of Catalysts


  Catalysts bring various benefits to industry, including environmental friendliness, increased operating profit, improved efficiency, and the ability to enable reactions that would not otherwise be possible.
• Disadvantages of Catalysts


  Catalysts may require an extra separation step to remove them, can become contaminated and lose effectiveness, require regeneration, and generate waste, which can add to production costs.
• Common Catalysts and Reactions

  Nickel is used in margarine production, vanadium(V) oxide in sulfuric acid production, iron in the Haber process, and platinum in nitric acid production and catalytic converters.
• Lower Activation Energy


  Lower activation energy allows particles to easily gain energy, leading to faster reactions and lower energy costs.
• Reverse Reaction


  A reverse reaction is a process that converts the products of the original reaction back into the original reactants by changing the conditions.
• Equilibrium Reaction


  Ammonium chloride crystals heat-up to form ammonia gas and hydrogen chloride gas, which then cool down to form ammonium chloride crystals. The forward and backward reactions are in equilibrium.
• Activation Energy


  Activation energy is the minimum energy required to break old bonds and start a chemical reaction, allowing new bonds to form.
• Exothermic/Endothermic


  Exothermic reactions release heat (get hot), while endothermic reactions absorb heat (get cold).
• Reversible Reactions


  A reversible reaction can be reversed by changing conditions, with the forward reaction's energy type opposite the reverse reaction's energy type (exothermic/endothermic).
• Le Châtelier's Principle


  In a reversible reaction, an increase in the concentration of a substance tips the equilibrium in the direction that consumes the added substance, restoring equilibrium.
• Concentration Change


  Changing the concentration of a reactant or product disturbs the equilibrium, and the system adjusts by changing concentrations until equilibrium is restored.
• Concentration Change Effect


  Increase reactant concentration: more products formed. Decrease product concentration: more reactants react. Both lead to equilibrium restoration.
• Equilibrium vs Dynamic


  Equilibrium: constant amounts; still occurring. Dynamic: reaction still occurring; rates of forward and reverse reactions equal.
• Equilibrium Factors


  Two factors that influence the position of an equilibrium: Temperature (for endothermic/exothermic reactions) and Concentration (or pressure in gas reactions).
• Temperature and Reaction Direction

  The hotter the reaction, the more likely it is to go in the endothermic direction (absorbs energy); colder the reaction, more likely to go in the exothermic direction (releases energy).
• Temperature Change Effect on Equilibrium

  Increase: endothermic - more products, exothermic - fewer products. Decrease: endothermic - fewer products, exothermic - more products.
• Effect of Pressure Change on Gas Equilibrium

  Increase in pressure: shifts towards side with fewer molecules. Decrease in pressure: shifts towards side with more molecules.