AP Chemistry Unit 3 Progress Check MCQ AP Scoring Guide

Which particle diagram shown above best represents the strongest intermolecular force between two ethanol, , molecules? Diagram 1, because it shows hydrogen bonds forming between hydrogen atoms from different ethanol A molecules. B Diagram 1, because it shows strong, directional dipole-dipole forces between two polar ethanol molecules. Diagram 2, because it shows the formation of a hydrogen bond between an atom bonded to an atom C with an atom from another molecule. Diagram 2, because it shows the dipole from an ethanol molecule inducing a dipole in another ethanol D molecule. 2. The diagram above represents four cations, all shown to the same scale. Which cation would be predicted by Coulomb’s law to have the strongest ion-dipole attraction to water, and why? AP Chemistry Scoring Guide Unit 3 Progress Check: MCQ A , because it is the smallest group 1 metal ion. B , because it has the largest charge-to-size ratio. C , because it has the smallest charge-to-size ratio. D , because it is the largest group 2 metal ion. 3. A solid compound of a group 1 (alkali) metal and a group 17 (halogen) element dissolves in water. The diagram above represents one type of solute particle present in the solution. Which of the following identifies the solute particle and best helps explain how the solute particle interacts with water molecules? AP Chemistry Scoring Guide Unit 3 Progress Check: MCQ A The particle is a negative ion, and the interactions are hydrogen bonds. B The particle is a negative ion, and the interactions are ion-dipole attractions. C The particle is a positive ion, and the interactions are ion-dipole attractions. D The particle is a positive ion, and the interactions are dipole-dipole attractions. 4. The diagrams above represent two allotropes of solid phosphorus. Which of the following correctly identifies the allotrope with the higher melting point and explains why? Allotrope , because it has molecules with covalent bonds that are stronger than dispersion forces A between individual atoms in allotrope . Allotrope , because it has covalent bonds between the phosphorous atoms that are stronger than the B dispersion forces between the molecules in allotrope . Allotrope , because it has metallic bonding that is stronger than the covalent bonding found in the C molecules in allotrope . D Both allotropes have the same melting point because they both contain phosphorous atoms