AP CHEM Unit 10 Exam POTENTIAL

Based on the data in the tables below, which of the following statements provides the best explanation for the higher boiling point for MgO?

• The charges of the ions are larger in MgO compared to NaF, creating larger Coulombic attractions. .

• The distance between the ions is smaller in MgO compared to NaF, creating larger Coulombic attractions.

• Oxygen is less electronegative than fluorine creating larger Coulombic attractions.

• MgO has a higher boiling point than NaF because the energy required to transfer electrons from the anion to the cation is larger in NaF than in MgO .

Tags

NGSS.HS-PS2-4

Of the following single bonds, which is the LEAST polar?

• H—F

• H—Cl

• H—Br

• H—I

Which of the following Lewis electron-dot diagrams represents the molecule that contains the smallest bond angle?

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• 
• 
• 

Which of the following diagrams shows the correct representation of the hydrogen bonding (denoted by dashed lines) between thymine and adenine base pairs?

• A 
• B 
• C 
• D 

Tags

NGSS.HS-LS1-1

To make Au stronger and harder, it is often alloyed with other metals. Consider two alloys, one of Au and Cu and one of Au and Ag. If the Au/Cu alloy is harder than the Au/Ag alloy, then which of the following is the best explanation based on the information in the table below?

• Cu has two common oxidation states, but Ag has only one.
• Cu has a higher melting point than Au has, but Ag has a lower melting point than Au has.
• Cu atoms are smaller than Ag atoms, thus they interfere more with the displacement of atoms in the alloy.
• Cu atoms are less polarizable than are Au or Ag atoms, thus Cu has weaker interparticle forces.

Tags

NGSS.HS-PS1-3

Which of the following could be the identity of a white crystalline solid that exhibits the following properties?
•It melts at 320° Celsius
•It does not conduct electricity as a solid.
•It conducts electricity in an aqueous solution.

• C₆H₁₂O₆(s)
• NaOH(s)
• SiO₂(s)
• Cu(s)

Tags

NGSS.HS-PS1-3

Which of the following is a list of the compounds in order of increasing boiling points?

• Butane < 1-propanol < acetone
• Butane < acetone < 1-propanol
• 1-propanol < acetone < butane
• Acetone = butane < 1-propanol

Benzene, C₆H₆ , has the structure shown above. Considering the observation that benzene is only sparingly soluble in water, which of the following best describes the intermolecular forces of attraction between water and benzene?

• Benzene is nonpolar, therefore there are no forces between water and benzene.

• The H atoms in benzene form hydrogen bonds with the O atoms in water.

• Benzene is hydrophobic, therefore there is a net repulsion between water and benzene.

• There are dipole-induced dipole and London dispersion interactions between water and benzene.

The following questions relate to the graph below. The graph shows the temperature of a pure substance as it is heated at a constant rate in an open vessel at 1.0 atm pressure. The substance changes from the solid to the liquid to the gas phase. Which of the following best describes what happens to the substance between t₄ and t₅?

• The molecules are leaving the liquid phase.

• The solid and liquid phases coexist in equilibrium.

• The vapor pressure of the substance is decreasing.

• The average intermolecular distance is decreasing.

Tags

NGSS.HS-PS3-4

Which of the following best helps to explain why the value of ΔH° for the dissolving of CaF₂ in water is positive?

• CaF₂(s) is insoluble in water.

• CaF₂(s) dissolves in water to form CaF2(aq) particles.

• Ca²⁺ ions have very strong ion-ion interactions with F- ions in the crystal lattice.

• Ca²⁺ ions have very strong ion-dipole interactions with water molecules in the solution.

Tags

NGSS.HS-PS1-3