Chemical reactions are all about change and balance. Reaction rates show how fast chemicals transform, influenced by factors like temperature and concentration. Understanding these helps us control reactions in labs and industry.

Chemical equilibrium is the steady state where forward and reverse reactions balance out. We can manipulate equilibrium systems using Le Chatelier's principle, which predicts how reactions respond to changes in conditions like pressure or temperature.

Reaction Rates

Factors Affecting Reaction Speed

• Reaction rate measures the speed of a chemical reaction by tracking changes in reactant or product concentrations over time
• Activation energy represents the minimum energy required for reactants to form products in a chemical reaction
• Catalysts accelerate chemical reactions by lowering the activation energy without being consumed in the process
• Concentration influences reaction rates as higher concentrations of reactants lead to more frequent collisions between particles, increasing the likelihood of successful reactions
• Temperature affects reaction rates by increasing the kinetic energy of particles, resulting in more frequent and energetic collisions

Measuring and Controlling Reaction Rates

• Reaction rates can be measured using various techniques such as spectrophotometry, conductivity measurements, or gas evolution
• The rate law expresses the relationship between reaction rate and reactant concentrations
• Order of reaction describes how the concentration of a specific reactant affects the overall reaction rate
• Rate-determining step represents the slowest step in a multi-step reaction, controlling the overall reaction rate
• Reaction mechanisms provide detailed step-by-step descriptions of how reactants transform into products during a chemical reaction

Chemical Equilibrium

Understanding Chemical Equilibrium

• Chemical equilibrium occurs when the forward and reverse reaction rates become equal, resulting in no net change in reactant and product concentrations
• Equilibrium constant (K) quantifies the relative concentrations of reactants and products at equilibrium
• Dynamic equilibrium involves continuous forward and reverse reactions occurring at the same rate
• Homogeneous equilibrium exists when all reactants and products are in the same phase
• Heterogeneous equilibrium involves reactants and products in different phases

Manipulating Equilibrium Systems

• Le Chatelier's principle predicts how a system at equilibrium responds to external changes by shifting to counteract the disturbance
• Pressure changes affect equilibrium systems involving gases, with increased pressure favoring the side with fewer gas molecules
• Temperature changes impact equilibrium, with endothermic reactions favored by increased temperature and exothermic reactions favored by decreased temperature
• Concentration changes shift equilibrium, with increased reactant concentration favoring product formation and vice versa
• Reversible reactions can proceed in both forward and reverse directions, allowing the system to reach equilibrium