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

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

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

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

23. When a nonvolatile solute is added to a volatile solvent, the solution vapor pressure , the boiling point _, the freezing point _, and the osmotic pressure across a semipermeable membrane . (A) decreases, increases, decreases, decreases (B) increases, increases, decreases, increases (C) increases, decreases, increases, decreases (D) decreases, decreases, increases, decreases (E) decreases, increases, decreases, increases

24. The destruction of a colloid is called (A) degeneration (B) coagulation (C) denaturation (D) reconfiguration (E) none of these

25. How many of the following molecules have all of their atoms in the same plane? H2C=CH2, F2O, H2CO, NH3, CO2, BeCl2, H2O2 (A) 3 (B) 4 (C) 5 (D) 6 (E) 7

26. What is the shape of the ICl5 molecule? (A) square pyramid (B) trigonal bipyramid (C) octahedral (D) see-saw (E) none of these