AP Chemistry Part B Flashcards

Module 5: Kinetics and Thermodynamics

Chemical Kinetics

• Reaction Rate: Change in concentration of reactants/products over time.
  
  

• Rate Laws: Expressed as Rate = k[A]^m[B]^n; determined experimentally.
  
  

  • Order of Reaction: Exponents (m and n); not necessarily stoichiometric coefficients.
    
    

• Integrated Rate Laws:
  

  • First order: ln[A] = -kt + ln[A]₀
    
    

  • Second order: 1/[A] = kt + 1/[A]₀
    
    

• Mechanisms: Series of elementary steps; rate-determining step limits speed.
  
  

• Catalysts: Lower activation energy; increase rate without being consumed.
  
  

Thermochemistry: Enthalpy

• System vs. Surroundings: Chemical system exchanges energy with its surroundings.
  
  

• Enthalpy (ΔH): Heat content at constant pressure.
  
  

  • Endothermic: Absorbs heat (ΔH > 0).
    
    

  • Exothermic: Releases heat (ΔH < 0).
    
    

• Calorimetry: Measures heat flow using q = mcΔT.
  
  

• Hess's Law: ΔH for an overall reaction = sum of ΔH for individual steps.
  
  

Entropy and Free Energy

• Entropy (S): Measure of disorder; always increases in spontaneous processes.
  
  

• Second Law of Thermodynamics: ΔS_universe = ΔS_system + ΔS_surroundings > 0 for spontaneity.
  
  

• Gibbs Free Energy:
  
  

  • ΔG = ΔH - TΔS
    
    

  • ΔG < 0 → Spontaneous
    
    

  • ΔG = 0 → At equilibrium
    
    

  • ΔG > 0 → Non-spontaneous
    
    

⚖ Module 6: Chemical Equilibrium

Dynamic Equilibrium

• Rate_forward = Rate_reverse; concentrations constant over time.
  
  

• Law of Mass Action: K=[products]n[reactants]mK = \frac{[products]^n}{[reactants]^m}K=[reactants]m[products]n​
  
  

Equilibrium Constants (K)

• Kc for concentration; Kp for gases (based on partial pressures).
  
  

• Large K → favors products; Small K → favors reactants.
  
  

• Q (reaction quotient): Compare Q to K to predict direction of reaction.
  
  

Le Chatelier’s Principle

• When a stress is applied (change in concentration, temperature, or pressure), the system shifts to relieve the stress.
  
  

• Examples:
  
  

  • Add reactant → shifts right
    
    

  • Increase pressure → shifts toward fewer moles of gas
    
    

  • Increase temp → favors endothermic direction
    
    

Solubility Equilibria

• Solubility Product Constant (Ksp): Ksp=[M+]a[A−]bK_{sp} = [M^+]^a[A^-]^bKsp​=[M+]a[A−]b
  
  

• Common Ion Effect: Solubility of a salt decreases in a solution containing a common ion.
  
  

Module 7: Acid-Base Reactions and Electrochemistry

Acids and Bases

• Arrhenius: Acids produce H⁺, bases produce OH⁻.
  
  

• Brønsted-Lowry: Acids donate H⁺, bases accept H⁺.
  
  

• Lewis: Acids accept e⁻ pair; bases donate e⁻ pair.
  
  

Strength and Equilibria

• Strong acids/bases dissociate completely (e.g. HCl, NaOH).
  
  

• Weak acids/bases partially dissociate → Ka and Kb quantify strength.
  
  

• Buffer Solutions: Resist pH changes; made from weak acid + conjugate base.
  
  

• Titration: Used to determine unknown concentrations; equivalence point = moles acid = moles base.
  
  

Electrochemistry

• Redox Reactions: Involve electron transfer.
  
  

• Galvanic Cells: Spontaneous; convert chemical energy into electrical.
  
  

  • Anode (oxidation), Cathode (reduction).
    
    

  • Electrons flow from anode → cathode.
    
    

• Cell Potential (E°cell):
  E°cell=E°cathode−E°anodeE°_{cell} = E°_{cathode} - E°_{anode}E°cell​=E°cathode​−E°anode​
  Positive E°cell = spontaneous
  
  

• Nernst Equation: Adjusts E for nonstandard conditions.
  
  

Module 8: Organic Chemistry

Hydrocarbons

• Alkanes: Single bonds, saturated (CnH₂n+2).
  
  

• Alkenes: Double bonds, unsaturated (CnH₂n).
  
  

• Alkynes: Triple bonds (CnH₂n-2).
  
  

• Aromatic Compounds: Benzene rings, delocalized π electrons.
  
  

Functional Groups

• Alcohols (-OH), Ethers (R-O-R), Aldehydes (-CHO), Ketones (C=O), Carboxylic Acids (-COOH), Esters (-COOR), Amines (-NH₂).
  
  

• Structure determines reactivity and physical properties.
  
  

Polymers

• Addition Polymers: Made from unsaturated monomers (e.g., polyethylene).
  
  

• Condensation Polymers: Monomers join with loss of small molecule (e.g., water); includes proteins, nylon, DNA.