16. Which of the following statements is true?
(A) we can determine the exact location of an electron if we know its energy
(B) an electron in a 2s orbital can have the same n, l, and m₁ quantum numbers as an electron in a 3s orbital
(C) Ni has 2 unpaired electrons in its 3d orbitals
(D) in the building up of atoms, electrons occupy the 4f orbitals before the 6s orbitals
(E) only three quantum numbers are needed to uniquely describe an electron

12. For a spontaneous endothermic process, which conditions must hold? (1)  = △G (2)  ＞ 0 (3) △S cannot be negative (4) △S is positive. (A) all (B) none (C) 1 and 3 only (D) 1, 2, and 4 only (E) 3 and 4 only

13. Choose the correct statement. (A) exothermic reactions are always spontaneous (B) free energy is independent of temperature (C) a reaction that exhibits a negative value of AS cannot be spontaneous (D) at constant pressure and temperature, a decrease in free energy ensures an increase in the entropy of the system (E) none of these

14. When the equation for the following reaction in basic solution is balanced, what is the sum of the coefficients? (A) 11 (B) 31 (C) 14 (D) 9 (E) 18

15. From the following list of observations, choose the one that most clearly supports the conclusion that electrons have wave properties. (A) the emission spectrum of hydrogen (B) the photoelectric effect (C) the scattering of alpha particles by metal foil (D) diffraction (E) cathode "rays"

17. Which of the following combinations of quantum numbers do not represent permissible solutions of the Schrodinger equation for the electron in the hydrogen atom? (In other words, which combination of quantum numbers is not allowed?) (Combinations are listed as follows: n, l, m(1), M(s).) (A) 9, 8, 4, 1/2 (B)8, 2, 2, 1/2 (C) 6, -5, -1, 1/2 (D) 6, 5, −5, 1/2 (E) all are allowed

18. For which element are the d orbitals completely filled in the neutral atom? (A) potassium (B) vanadium (C) phosphorus (D) iron (E) bromine

19. The rate law for a reaction is found to be Rate = k〔A〕2〔B〕. Which of the following mechanisms gives this rate law?   (A) I only (B) II only (C) III (D) two of these (E) none of these

20. Rank the following compounds according to increasing solubility in water. I: CH3-CH2-CH2-CH3, II: CH3-CH2-O-CH2-CH3, III: CH3-CH2-OH, IV: CH3-OH (A) I ＜ III ＜ IV ＜ II (B) I ＜ II ＜ IV ＜ III (C) III ＜ IV ＜ II ＜ I (D) I ＜ II ＜ III ＜ IV (E) none is correct

21. Solid KF has a lattice energy of -804 kJ/mol and a heat of solution (in water) of -15 kJ/mol. RbF has a lattice energy of -768 kJ/mol and a heat of solution (in water) of -24 kJ/mol. Which salt forms stronger attractions with water? (A) KF, because it has a more exothermic lattice energy (B) RbF, because it has a less exothermic lattice energy (C) KF, because it has a more negative heat of hydration (D) RbF, because it has a more negative heat of hydration (E) they form equally strong attractions with water, because they both have negative heats of mixing

22. Liquid A has vapor pressure x. Liquid B has vapor pressure y, and x ＞ y. What is the mole fraction of A in the liquid mixture if the vapor above the solution is 30% A? (A) 0.3y/(0.7x + 0.3y) (B) 0.7y/(0.3x + 0.7y) (C) 0.3x/(0.3x + 0.7y) (D) 0.7x/(0.7x + 0.3y) (E) none of these