11) Which of the following statements concerning molecules in the liquid state is true? A) Cohesive forces are not important. B) The molecules contract to fit the size of the container. C) The molecules have no motion. D) The molecules are in a patterned (oriented) arrangement. E) The molecules are mobile and relatively close together. 12) Which probably has the lowest boiling point at 1.0 atm pressure? A) PbH4 B) SnH4 C) SiH4 D) GeH4 E) CH4 13) Which probably has the lowest boiling point at 1.0 atm pressure? A) C2H6 B) C4H10 C) C6H14 D) C3H8 E) C5H12 14) If one compares compound A, composed of nonpolar molecules, with compound B, composed of polar molecules, and both molecules have the same molecular formula, then it is true that: A) both compounds have the same boiling point B) A boils at a lower temperature than B C) B will not boil D) B boils at a lower temperature than A E) we have to know the structural formula to determine the differences in boiling points of A and B 15) Below are given the Lewis structures of five molecules. Which one displays the LEAST hydrogen bonding? 16) Below are given the Lewis structures of five molecules. Which one displays the MOST hydrogen bonding? 17) Which of the following compounds has the highest boiling point? A) NH3 B) H2O C) HF D) CH4 E) HBr 18) Which probably has the highest boiling point at 1.00 atm pressure? A) H2NCH2CH2NH2 B) CH3CH2CH2NH2 C) (CH3)2CHNH2 D) CH3CH2NHCH3 E) (CH3)3N 19) A liquid will “wet” a surface if: A) the liquid has a lesser density than the surface B) the forces between the liquid molecules are weak C) the liquid has a low vapor pressure D) the forces between the molecules and the surface are greater than the forces between the molecules of the liquid E) The liquid has low viscosity and the surface is smooth 20) Surface tension is thought to be due to: A) surface area trying to increase B) air absorbed on the surface C) solute concentrated on the surface D) surface molecules having lower energy than bulk molecules E) surface molecules having higher energy than molecules in the bulk