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General Chemistry I · High-yield review

General Chemistry I — High-Yield Review

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On this page 2 sections
  1. In 30 seconds
  2. The college version

In 30 seconds

A condensed, exam-focused review of all 28 topics. Use after working through the topic files.

The college version

Highest-Yield Facts and Equations

  • High yield: Dimensional analysis: convert with labeled factors; carry units; check sig figs.
  • High yield: Average atomic mass = Σ (isotope mass × fractional abundance).
  • High yield: Moles: n = m/M; Avogadro's number 6.022 × 10²³.
  • High yield: Percent yield = (actual/theoretical) × 100; identify limiting reactant first.
  • High yield: Molarity M = mol/L; dilution M₁V₁ = M₂V₂.
  • High yield: q = mcΔT (specific heat); ΔH = ΣΔH°f(products) − ΣΔH°f(reactants); Hess's law.
  • High yield: E = hν; c = λν; photon energy (Planck).
  • High yield: Quantum numbers n, l, ml, ms; Aufbau, Pauli, Hund.
  • High yield: Zeff = Z − shielding; trends: radius ↓ across period, ↑ down group; ionization energy ↑ across period.
  • High yield: VSEPR → molecular geometry; polarity needs bond polarity + shape.
  • High yield: PV = nRT (ideal gas; use Kelvin); Dalton's law P_total = ΣP_i; Graham's law.

Comparison Tables

Do not confuseWithDifference
AccuracyPrecisionCloseness to true value vs reproducibility
Physical changeChemical changeIdentity unchanged vs new substance
Empirical formulaMolecular formulaSimplest ratio vs actual count
Limiting reactantExcess reactantConsumed first vs leftover
HeatTemperatureEnergy transfer vs average kinetic energy
ExothermicEndothermicReleases heat (ΔH<0) vs absorbs heat (ΔH>0)
FrequencyWavelengthCycles/time vs distance/cycle (inversely related)
OrbitalOrbitProbability region vs fixed path
Electron-domain geometryMolecular geometryIncludes lone pairs vs atoms only
Sigma bondPi bondHead-on overlap vs side-on overlap
Bond orderBond lengthHigher order = shorter/stronger
Ideal gasReal gasNo intermolecular forces vs deviates at high P/low T

Cumulative Self-Check (20 questions)

  1. How many significant figures in 0.00450?
  2. Convert 25°C to Kelvin.
  3. Define a mole.
  4. What is the formula for percent yield?
  5. Define molarity.
  6. Write the dilution equation.
  7. What is the first law of thermodynamics?
  8. Distinguish exothermic from endothermic.
  9. Write the equation relating energy, frequency, and wavelength of light.
  10. List the four quantum numbers and what each specifies.
  11. State Hund's rule.
  12. Why do Cr and Cu have anomalous electron configurations?
  13. State the periodic trend for atomic radius across a period and down a group.
  14. What does VSEPR stand for, and what does it predict?
  15. When is a molecule polar?
  16. Write the ideal gas law.
  17. Why must temperature be in Kelvin for gas calculations?
  18. State Dalton's law of partial pressures.
  19. What does Graham's law describe?
  20. What is the difference between a sigma and a pi bond?

Answers and Rationales

  1. Three (leading zeros are not significant; the trailing zero after 5 is).
  2. 298 K (25 + 273.15).
  3. 6.022 × 10²³ particles (Avogadro's number).
  4. (actual/theoretical) × 100.
  5. Moles of solute per liter of solution.
  6. M₁V₁ = M₂V₂.
  7. Energy is conserved (ΔE = q + w).
  8. Exothermic releases heat (ΔH<0); endothermic absorbs heat (ΔH>0).
  9. E = hν and c = λν.
  10. n (size/energy), l (shape/sublevel), ml (orientation), ms (spin).
  11. Degenerate orbitals fill singly before pairing.
  12. Half-filled/filled d subshells are extra stable.
  13. Radius decreases across a period (↑Zeff) and increases down a group (more shells).
  14. Valence Shell Electron Pair Repulsion — predicts molecular geometry.
  15. When bond dipoles do not cancel (depends on shape).
  16. PV = nRT.
  17. Gas laws are absolute-temperature relationships; 0 K = absolute zero.
  18. Total pressure = sum of partial pressures.
  19. Effusion/diffusion rates vary inversely with √molar mass.
  20. Sigma = end-to-end overlap; pi = side-by-side overlap.

Last-Minute Review

  • Measurements: sig figs, metric prefixes, dimensional analysis.
  • Stoichiometry: mole conversions, balancing, limiting reactant, yield.
  • Solutions: molarity, dilution, net ionic equations, redox.
  • Thermochemistry: q = mcΔT, enthalpy, Hess's law, formation enthalpies.
  • Electronic structure: light (E = hν), Bohr, quantum numbers, electron configurations.
  • Periodicity: Zeff, radius/ionization/electronegativity trends.
  • Bonding: Lewis, formal charge, VSEPR, hybridization, MO/bond order.
  • Gases: gas laws (Kelvin!), Dalton, Graham, KMT, real-gas deviations.

Related

  • Subject overview
  • Topic 05 — The Mole and Molar Mass
  • Topic 12 — Enthalpy
  • Topic 26 — The Gas Laws

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Practice General Chemistry I

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