GRE Chemistry Domain 4: Physical Chemistry Welcome to your GRE Chemistry Domain 4: Physical Chemistry 1. GRE Chemistry: Physical Chemistry In a chemical reaction at equilibrium, which of the following changes will shift the equilibrium position to the right according to Le Chatelier's Principle? A. Increasing the concentration of reactants. B. Decreasing the concentration of products. C. Increasing the temperature for an exothermic reaction. D. Decreasing the pressure by increasing the volume. None 2. GRE Chemistry: Physical Chemistry What is the effect of a catalyst on the equilibrium constant (K) of a reversible chemical reaction? A. It increases K. B. It decreases K. C. It does not change K. D. It changes K based on the reaction temperature. None 3. GRE Chemistry: Physical Chemistry What is the primary reason for the increase in entropy (disorder) in a system when a solid dissolves in a solvent? A. The formation of solvent-solute interactions. B. The increase in total volume of the solution. C. The increase in the number of ways to arrange the particles. D. The release of heat during the dissolution process. None 4. GRE Chemistry: Physical Chemistry In quantum mechanics, the Heisenberg Uncertainty Principle primarily asserts that: A. The position and momentum of a particle can be precisely determined simultaneously. B. The energy and lifetime of an excited state can be exactly known at the same time. C. It is impossible to simultaneously determine the exact position and momentum of a particle. D. The spin and charge of an electron can be precisely measured at the same time. None 5. GRE Chemistry: Physical Chemistry In electrochemistry, what is the Nernst equation primarily used to calculate? A. The standard electrode potential. B. The equilibrium constant of a redox reaction. C. The cell potential under non-standard conditions. D. The rate of an electrochemical reaction. None 6. GRE Chemistry: Physical Chemistry What does the term "kinetic isotope effect" refer to in chemical kinetics? A. The change in reaction rate due to the substitution of an atom by its isotope. B. The change in equilibrium position when isotopes are used. C. The effect of isotopes on the activation energy of a reaction. D. The difference in chemical properties between isotopes. None 7. GRE Chemistry: Physical Chemistry In a chemical reaction obeying Arrhenius equation, what effect does an increase in temperature have on the rate constant (k)? A. k remains constant. B. k decreases. C. k increases. D. The effect cannot be determined. None 8. GRE Chemistry: Physical Chemistry The term "phase diagram" in physical chemistry is best described as: A. A graphical representation of the solubility of a substance. B. A chart showing the standard electrode potentials of elements. C. A diagram showing the states of matter of a substance under different temperatures and pressures. D. A schematic of the molecular structure of a compound. None 9. GRE Chemistry: Physical Chemistry In a reaction where the rate-determining step is the second step of a multi-step mechanism, which of the following is most likely true? A. The intermediates formed in the first step are irrelevant to the overall rate. B. The activation energy of the first step is the highest. C. The overall reaction rate depends on the concentration of intermediates formed in the first step. D. The rate law can be determined by the stoichiometry of the overall reaction. None 10. GRE Chemistry: Physical Chemistry In a gas mixture, Dalton's Law of Partial Pressures states that the total pressure is: A. Equal to the pressure of the most abundant gas. B. The average of the pressures of each individual gas. C. Equal to the sum of the partial pressures of each individual gas. D. Dependent on the volume and temperature of the gas mixture. None 11. GRE Chemistry: Physical Chemistry In the context of molecular orbital theory, which of the following statements accurately describes a bonding molecular orbital? A. It is formed by the destructive interference of atomic orbitals. B. It has higher energy compared to the corresponding antibonding molecular orbital. C. It is formed by the constructive interference of atomic orbitals. D. It is always non-bonding in nature. None 12. GRE Chemistry: Physical Chemistry For a reaction that follows the Arrhenius equation, what is the significance of the Arrhenius pre-exponential factor ( A. A) It represents the frequency of collisions with correct orientation. B. It is directly proportional to the activation energy. C. It indicates the temperature dependence of the reaction. D. It is inversely proportional to the rate constant. None 13. GRE Chemistry: Physical Chemistry In a system at equilibrium, what is the relationship between the rates of the forward and reverse reactions? A. The rate of the forward reaction is zero. B. The rate of the reverse reaction is higher. C. The rates of the forward and reverse reactions are equal. D. The rates of the forward and reverse reactions are independent of each other. None 14. GRE Chemistry: Physical Chemistry What is the primary characteristic of a reaction that follows zero-order kinetics? A. The rate of reaction is independent of the concentration of the reactant. B. The rate of reaction decreases linearly with time. C. The half-life of the reaction is proportional to the initial concentration. D. The rate of reaction is proportional to the concentration of the reactant. None 15. GRE Chemistry: Physical Chemistry What is the primary assumption of the collision theory of chemical kinetics? A. All collisions between reactant molecules lead to a reaction. B. The activation energy of a reaction depends on temperature. C. Only a fraction of collisions have the correct orientation and sufficient energy to lead to a reaction. D. The reaction rate is independent of the molecular orientation during collision. None 16. GRE Chemistry: Physical Chemistry In quantum mechanics, what does the Pauli Exclusion Principle state about electrons in an atom? A. Electrons in the same orbital must have opposite spins. B. No two electrons can occupy the same quantum state simultaneously. C. Electrons always pair up in an orbital. D. Electrons repel each other due to their negative charge. None 17. GRE Chemistry: Physical Chemistry What is the primary function of a buffer solution? A. To change the pH of a solution drastically. B. To maintain a constant pH upon the addition of small amounts of acid or base. C. To increase the solubility of solutes in a solution. D. To catalyze reactions in the solution. None 18. GRE Chemistry: Physical Chemistry Which principle explains the increase in entropy when a solute dissolves in a solvent? A. Le Chatelier's Principle. B. The Gibbs-Helmholtz Equation. C. Raoult's Law. D. The Second Law of Thermodynamics. None 19. GRE Chemistry: Physical Chemistry In the context of electrochemistry, what does a positive electrode potential indicate? A. The electrode is a strong reducing agent. B. The electrode is a strong oxidizing agent. C. The reaction is non-spontaneous. D. The electrode is undergoing reduction. None 20. GRE Chemistry: Physical Chemistry In a chemical reaction, the transition state refers to: A. The stable state of reactants before the reaction starts. B. The intermediate state between reactants and products with the highest potential energy. C. The final stable state of the products. D. The state where reactants and products are in dynamic equilibrium. None 21. GRE Chemistry: Physical Chemistry In the context of statistical thermodynamics, the Maxwell-Boltzmann distribution primarily describes the: A. Distribution of energies among molecules in a gas at a specific temperature. B. Number of collisions per second in a gas. C. Rate of diffusion of gas molecules. D. Pressure exerted by a gas on the walls of its container. None 22. GRE Chemistry: Physical Chemistry What is the significance of the term "enthalpy" (H) in a chemical reaction? A. It represents the total kinetic energy of the system. B. It is the heat content of a system at constant pressure. C. It denotes the work done by the system. D. It is the measure of the disorder of the system. None 23. GRE Chemistry: Physical Chemistry In a homogenous catalysis, the catalyst: A. Is in a different phase than the reactants. B. Forms a transient complex with the reactants. C. Remains unchanged after the reaction. D. Increases the activation energy of the reaction. None 24. GRE Chemistry: Physical Chemistry The Clausius-Clapeyron equation is used to estimate: A. The change in enthalpy of vaporization. B. The equilibrium constant of a reaction. C. The rate of a chemical reaction. D. The heat capacity of a gas. None 25. GRE Chemistry: Physical Chemistry In quantum chemistry, the term "orbital hybridization" refers to: A. The mixing of different atomic orbitals to form new hybrid orbitals. B. The transition of electrons between orbitals of different energies. C. The combination of orbitals to form molecular orbitals. D. The overlap of atomic orbitals to form chemical bonds. None 26. GRE Chemistry: Physical Chemistry The Lindemann mechanism is often used to describe: A. The rate of unimolecular reactions. B. The equilibrium in chemical reactions. C. The formation of coordination complexes. D. The electron transfer in redox reactions. None 27. GRE Chemistry: Physical Chemistry In a chemical system, the term "activity" is best described as: A. The concentration of a species in a reaction. B. The effective concentration of a species in a non-ideal solution. C. The rate of reaction of a species. D. The energy required to activate a species. None 28. GRE Chemistry: Physical Chemistry The term "Hammett equation" in physical organic chemistry is used to relate: A. The reaction rate to the pKa of the solvent. B. The equilibrium constant to the structure of the reactants. C. The effect of substituents on the reactivity of aromatic compounds. D. The solubility of a compound to its molecular weight. None 29. GRE Chemistry: Physical Chemistry In a reaction mechanism, a "rate-determining step" is characterized by: A. The fastest step in the mechanism. B. The step with the highest activation energy. C. The step that involves the most molecules. D. The final step in the mechanism. None 30. GRE Chemistry: Physical Chemistry In the context of molecular orbital theory, which of the following statements accurately describes a bonding molecular orbital? A. It is formed by the destructive interference of atomic orbitals. B. It has higher energy compared to the corresponding antibonding molecular orbital. C. It is formed by the constructive interference of atomic orbitals. D. It is always non-bonding in nature. None 1 out of 30 Time is Up! Time's up
