71 At 25^oC, iodine exists as a solid and bromine as a liquid. This
 difference in phase is due to the presence of stronger

(1) covalent bonds in iodine
(2) covalent bonds in bromine
(3) van der Waals forces in iodine
(4) van der Waals forces in bromine

Group 4 - Periodic Table

If you choose this group, be sure to answer questions 72-76.

72 A characteristic of a nonmetal is

(1) low ionization energy
(2) high electronegativity
(3) high electrical conductivity
(4) the ability to form positive ions

73 Which ionic compound dissolves in water to form a colored 
solution?

(1) Ca(NO₃)₂             (3) KNO₃
(2) Cu(NO₃)₂             (4) Al(NO₃)₃

74 Which element has a total of 5 valence electrons present in the 
fifth energy level?

(1) Sb            (3) I
(2) Bi            (4) Br

75 For which element is the ionic radius larger than the atomic radius?

(1) Na           (3) Al
(2) Mg          (4) Cl

76 Element X is in Group 2 and element Y is in Group 17. What
happens when a compound is formed between these two atoms?

(1) X loses electrons to Y to form an ionic bond.
(2) X loses electrons to Y to form a covalent bond.
(3) X gains electrons from Y to form an ionic bond.
(4) X gains electrons from Y to form a covalent bond.

Group 5 - Mathematics of Chemistry

If you choose this group, be sure to answer questions 77-81.

77 Approximately how many calories of heat are needed to completely
change 10 grams of ice to water at the melting point temperature?

(1) 1 cal             (3) 80 cal
(2) 8 cal             (4) 800 cal

78 What is the gram molecular mass of a gas that has a density of 
5.00 grams per liter at STP?

(1) 27.4 g            (3) 112 g
(2) 56.0 g            (4) 223 g

79 A compound consists of 25.9% nitrogen and 74.1% oxygen by
mass. What is the empirical formula of the compound?

(1) NO         (3) N₂O
(2) NO₂        (4) N₂O₅

80 A solution is formed by dissolving 45 grams of NH₄Cl in 100
grams of H₂O at 70^oC. Which statement correctly describes this
solution?

(1) NH₄Cl is the solute, and the solution is saturated.
(2) NH₄Cl is the solute, and the solution is unsaturated.
(3) NH₄Cl is the solvent, and the solution is saturated.
(4) NH₄Cl is the solvent, and the solution is unsaturated.