ID: A

40. ANS: C OW: 13.8 Other Kinds of Solid Materials

4!. ANS: E OW: 13.9 The Physical Properties of Solids

42. ANS: B OW: l3.lOPhasediagrams

43. ANS: C 081: 13.IOPhasediagrams

SHORT ANSWER

44. ANS:

Ca will have the more negative enthalpy of hydration. A calcium ion is smaller than a potassium ion. The smaller ion will bond more closely to water’s dipole, allowing for a stronger ion-dipole interaction. In addition, the higher the charge on the ion, the greater the ion-dipole interaction.

45. ANS:

White phosphorus is a molecular solid composed of tetrahedral P molecules. The P molecules are held together by London dispersion forces. Red phosphorus is a network solid; all phosphorus atoms are connected through covalent bonds. It is easier to disrupt the weaker London dispersion forces of P than it is to break the covalent bonds of red phosphorus.