Chemical Kinetics and Equilibrium Quiz

Chemical Kinetics

• Rate law determines the rate of a chemical reaction
• The rate law can be affected by several factors such as concentration, temperature, and the presence of a catalyst

Chemical Equilibrium

• Chemical equilibrium is reached when the rate of the forward reaction equals the rate of the reverse reaction
• The Law of Mass Action states that the equilibrium constant (Kc) is dependent on reactant and product concentrations and their coefficients
• Kc is independent of initial reactant/product concentrations, pressure changes (for gases), and the addition of a catalyst
• Forward reaction favors the formation of products while the reverse reaction favors the formation of reactants
• Kp is the equilibrium constant for gas species, relying on pressure instead of molarity
• Higher pressure shifts the equilibrium towards fewer gas moles, lower pressure favors more gas moles
• Homogeneous equilibrium occurs when reactants and products are in the same phase, heterogeneous equilibrium occurs when they are in different phases
• The following formulas can be used to calculate Kc:
  • Kc = [product concentration] / [reactant concentration]
  • Kc = Rate forward / Rate backward
• Multiple equilibria can have their Kc values multiplied: Kc = Kc’ x Kc’’ x Kc’’’...
• The reaction quotient (Qc) is dependent on initial concentrations, while the equilibrium constant (Kc) is dependent on equilibrium concentrations

Ionic Equilibria

• Arrhenius theory indicates that acids release H+ or H3O+ ions and bases release OH- ions in aqueous solutions
• Bronsted-Lowry theory is a protonic concept stating that acids donate protons while bases accept them
• Lewis theory is an electronic concept where acids are electron acceptors, and bases are electron donors
• Lewis theory explains electrophiles (electron-loving, often acids) and nucleophiles (electron-rich, often bases)
• Lewis acids are often metals or positively charged ions (cations), Lewis bases are typically nonmetals or negatively charged ions (anions)
• Strong electrolytes are strong conductors of heat and electricity and fully dissociate in water (irreversible reactions), including strong acids (SA), strong bases (SB), and salts
• Weak electrolytes partially ionize in water (reversible reactions), including weak acids (WA) and weak bases (WB)
• Non-electrolytes are typically organic compounds (e.g., hydrocarbons) and carbohydrates (e.g., glucose)
• Conjugates are ionized species:
  • Conjugate Acid (CA) - Add 1 H+ ion to the substance
  • Conjugate Base (CB) - Remove 1 H+ ion to the substance
• Organic compound acidity is influenced by electron-donating groups (EDGs) and electron-withdrawing groups (EWGs):
  • EDGs lower acid strength (examples: -CH3, -NO2, -CN, -COOH)
  • EWGs increase acid strength (examples: -OH, -NH2, alkyl groups)
• The following formulas are relevant to pH and pOH:
  • pH = -log[H+] and pOH = -log[OH-] are applicable for strong acids and bases respectively (Arrhenius theory)
  • pH = -log√KaCa and pOH = -log√KbCb for strong and weak acids/bases
  • % ionization = (√KaCa / Ca) x 100%
• Salts containing small and highly-charged cations produce acidic salts upon dissociation
• Salts of Weak Acids and Weak Bases:
  • Ka = Kb; Neutral Salt
  • Ka > Kb; Acidic Salt
  • Ka < Kb; Basic Salt

Acid-Base and Solubility Equilibria

• Buffer solutions resist changes in pH, with buffer capacity indicating the strength of this resistance
• The solubility product constant (Ksp) is not equal to the equilibrium constant (Kc)
• Complex ions (coordination compounds) consist of a central metal cation bonded to ligands (molecules or ions)
• Coordination number = total number of atoms, ions, or molecules bonded to the central atom

Test your knowledge on chemical kinetics and equilibrium. This quiz covers rate laws, factors affecting reaction rates, and the principles of chemical equilibrium including the Law of Mass Action and equilibrium constants. Challenge yourself with questions on both homogeneous and heterogeneous equilibria.