Study guide
This chapter is educational content only, not medical advice, and does not guarantee any exam outcome. It follows the AAMC's Foundational Concept 4 together with the general-chemistry material folded into Foundational Concept 5. On the real exam this content is tested almost entirely through Chem/Phys section passages that embed a physics or general-chemistry setup inside a biological or clinical scenario.
Fluids: Pressure, Flow, and the Circulatory System
Covers hydrostatic pressure (P = rho*g*h), the continuity equation, Bernoulli's equation, Poiseuille's law (r^4 dependence), and laminar vs. turbulent flow (Reynolds number) as applied to blood flow.
Electrochemistry and Electrical Circuits
Covers redox/OIL RIG, galvanic vs. electrolytic cells, E-cell = E-cathode - E-anode, the free-energy/cell-potential relation DG = -nFE, Ohm's law, and series/parallel resistor combination rules, tied to neuronal membrane analogy.
Thermodynamics and Kinetics
Covers first law, enthalpy, entropy, DG = DH - TDS and temperature-dependent spontaneity, distinction between thermodynamic favorability and kinetic rate, reaction order from data, Hess's law, and calorimetry.
Atomic and Nuclear Structure
Covers Aufbau/Pauli/Hund rules, periodic trends (radius, ionization energy, electronegativity), and nuclear decay modes (alpha, beta-minus, gamma) with half-life as first-order decay.
Optics and Sound
Covers thin-lens equation, magnification, Snell's law/total internal reflection, decibel scale (logarithmic), Doppler effect, and wave interference, tied to vision/hearing and Doppler ultrasound.
Gas Laws and Solution Equilibria
Covers ideal gas law, Boyle's law, Dalton's law of partial pressures, Henry's law (gas exchange in lungs/blood), Le Chatelier's principle, Henderson-Hasselbalch buffers, and colligative properties/osmotic pressure.
Key terms
- Poiseuille's law
- — Q = pi*r^4*(P1-P2)/(8*eta*L); flow rate scales with radius to the fourth power.
- Bernoulli's equation
- — P + (1/2)*rho*v^2 + rho*g*h = constant; faster horizontal flow means lower static pressure.
- Standard reduction potential (E-standard)
- — Measures a species' tendency to be reduced; E-cell = E-cathode - E-anode predicts spontaneity.
- Gibbs free energy (DG)
- — DG = DH - TDS; negative DG means spontaneous, and temperature can flip its sign.
- Activation energy (Ea)
- — Energy barrier lowered by catalysts without changing DG or Keq.
- Half-life
- — Constant time for half a radioactive sample to decay, independent of starting amount.
- Alpha decay
- — Emits a helium nucleus, reducing atomic number by 2 and mass number by 4.
- Thin-lens equation
- — 1/f = 1/do + 1/di relates focal length, object distance, and image distance.
- Henry's law
- — Dissolved gas concentration is proportional to its partial pressure above the liquid.
- Henderson-Hasselbalch equation
- — pH = pKa + log([A-]/[HA]); defines buffer pH and effective range.
Exam tips
- Separate continuity-equation (speed) questions from Bernoulli (pressure) questions on the same passage.
- Memorize Poiseuille's r^4 dependence to avoid wrong-exponent traps.
- Decide series vs. parallel before calculating circuit resistance changes.
- Do not conflate DG sign with reaction rate/Ea.
- Balance both mass and atomic number in nuclear decay questions.
- Apply Dalton's law to get each gas's own partial pressure before using Henry's law.