37. What Group 6A elements are semiconductors?
(A) selenium and polonium
(B) sulfur and tellurium
(C) sulfur and selenium
(D) selenium and tellurium
(E) tellurium and polonium

33. A liquid placed in a closed container will evaporate until equilibrium is reached. At equilibrium, which of the following statements is not true? (A) liquid molecules are still evaporating (B) the number of vapor molecules remains essentially constant (C) the partial pressure exerted by the vapor molecules is called the vapor pressure of the liquid (D) the boundary (meniscus) between the liquid and the vapor disappears (E) all of these statements are true.

34. How many different possible tetramethylbenzenes exist? (A) 6 (B)2 (C) 5 (D)3(E)4

35. Oxidation of a primary alcohol results in a(n)_____， and oxidation of a secondary alcohol results in a(n)_____. (A) ester, ether (B) ketone, aldehyde (C) amine, carboxylic acid (D) carboxylic acid, amine (E) aldehyde, ketone

36. Choose the correct molecular structure for .(A) octahedral (B) tetrahedral (C) trigonal planar (D) trigonal bipyramidal (E) linear

38. Which is the most reactive form of phosphorus? (A) white phosphorus (B) red phosphorus (C) black phosphorus (D) two of these forms of phosphorus are equally reactive (E) all of these forms of phosphorus are equally reactive

39. When a non volatile 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, decreases, increases, decreases (B)J increases, decreases, increases, decreases (C) decreases, increases, decreases, increases (D) increases, increases, decreases, increases (E) decreases, increases, decreases, decreases

40. Which of the following statements is(are) true? (A) the rate of dissolution of a solid in a liquid always increases with incr reasing temperature (B) the solubility of a solid in a liquid always increases with increasing temperature (C) according to Henry's law, the amount of gas dissolved in a solution is directly proportional to the pressure of the gas above the liquid (D) two of these statements are true (E) all of these statements are true.

41. Which statement regarding water is true? (A) liquid water is less dense than solid water.(B) only covalent bonds are broken when ice melts (C) hydrogen bonds are stronger than covalent bonds (D) energy must be given off in order to break down the crystal lattice of ice to a liquid (E) all of these statements are false.

42. Which of the following is the smallest hole in a closest-packed lattice of spheres? (A) trigonal (B) cubic (C) tetrahedral (D) octahedral (E) none of these

43. The unit cell in a certain lattice consists of a cube formed by an anion at each corner, an anion in the center, and a cation at the center of each face. The unit cell contains a net (A) 2 anions and 3 cations (B) 2 anions and 2 cations (C) 5 anions and 3 cations (D) 3 anions and 4 cations (E) 5 anions and 6 cations.