Paper IV — Chemistry
30 QUESTIONS
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1.
Is a chemical bond a thing or a model? Answer with reference to the electron density.
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2.
Explain why the concept of oxidation state is useful despite being formally arbitrary.
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3.
Derive the relationship between equilibrium constant and Gibbs free energy, and say what assumptions it hides.
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4.
Why is water anomalous? Give the molecular account.
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5.
What does it mean for a reaction to be "under kinetic" versus "thermodynamic" control?
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6.
Explain aromaticity without invoking the word "resonance."
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7.
Is the periodic table's structure a consequence of quantum mechanics alone, or does chemistry add something?
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8.
What is the physical basis of electronegativity, and why do scales disagree?
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9.
Account for the catalytic power of enzymes in thermodynamic and kinetic terms.
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10.
Why is the Born–Oppenheimer approximation so good, and when does it fail?
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11.
Explain chirality's consequences for reactivity and for biology.
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12.
What limits the accuracy of density functional theory in principle?
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13.
Give a molecular account of why entropy can drive assembly (e.g., the hydrophobic effect).
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14.
What is a transition state, and in what sense does it exist?
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15.
Explain the origin of colour in transition-metal complexes.
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16.
Why can a catalyst change a rate but not an equilibrium?
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17.
What does "electron correlation" mean, and why is it computationally expensive?
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18.
Explain how the Marcus theory of electron transfer predicts an inverted region.
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19.
Is the concept of a molecular orbital observable?
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20.
Account for the strength and directionality of the hydrogen bond.
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21.
Why is nitrogen fixation so difficult, industrially and biologically?
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22.
What determines whether a solid is a metal, semiconductor, or insulator, chemically?
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23.
Explain the thermodynamic driving force for protein folding.
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24.
What is autocatalysis, and why is it relevant to the origin of life?
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25.
Give the basis of the Woodward–Hoffmann rules.
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26.
Why do reaction rates so often follow the Arrhenius form, and when do they not?
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27.
What is measured by a standard electrode potential, and against what?
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28.
Explain the concept of a potential energy surface and its dimensionality.
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29.
Is supramolecular chemistry a distinct science or applied physics?
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30.
Which single unmeasured quantity, if known exactly, would most advance chemical prediction?