UNE General Chemistry II Midterm Actual Exam with Verified Questions and Answers Latest Edition Instant Pdf Download

UNE General Chemistry II Midterm Actual Exam
with Verified Questions and Answers Latest
Edition Instant Pdf Download.




SECTION 1: INTERMOLECULAR FORCES & PHASE CHANGES

1. A hydrogen bond is characterized by:

 A) The attraction of temporary dipoles produced by random asymmetries in
electron motion
 B) The electrostatic attraction between the permanent dipoles in any polar
molecule
 C) The highly concentrated partial charge between an H atom and F, O, or N
atoms
 D) The covalent sharing of electrons between two atoms in a molecule

Correct answer is C. A hydrogen bond is a special type of dipole-dipole interaction that
occurs when a hydrogen atom is bonded to a highly electronegative atom (F, O, or N). The
partial positive charge on H is strongly attracted to the partial negative charge on F, O, or
N of another molecule .

,2. Which of the following will have the strongest dipole-dipole attractions?

 A) NCl₃
 B) CCl₄
 C) BCl₃
 D) Cl₂

Correct answer is A. NCl₃ is asymmetrical and has a significant dipole moment. CCl₄ and
Cl₂ are nonpolar, and BCl₃ is trigonal planar and nonpolar. Nitrogen is more
electronegative than boron, making NCl₃ more polar .




3. A cohesive force is:

 A) The result of the intermolecular forces that attract identical molecules
 B) The result of the intermolecular forces that attract different molecules together
 C) The result of covalent interactions between atoms in a molecule
 D) Always stronger than an adhesive force

Correct answer is A. Cohesive forces are intermolecular attractions between identical
molecules. Adhesive forces are attractions between different molecules. Cohesion is
responsible for surface tension .




4. An adhesive force is:

 A) The result of the intermolecular forces that attract identical molecules
 B) The result of the intermolecular forces that attract different molecules
together
 C) The result of covalent interactions between atoms in a molecule

,  D) Always stronger than a cohesive force

Correct answer is B. Adhesive forces are intermolecular attractions between different types
of molecules. These forces are responsible for phenomena like capillary action .




5. Which of the following intermolecular forces is present in all molecules?

 A) Hydrogen bonding
 B) Dipole-dipole interactions
 C) London dispersion forces
 D) Ionic bonding

Correct answer is C. London dispersion forces (LDFs) are present in all molecules due to
temporary fluctuations in electron distribution. They are the only intermolecular force in
nonpolar molecules .




6. Which substance would have the highest boiling point?

 A) H₂O
 B) H₂S
 C) H₂Se
 D) H₂Te

Correct answer is A. H₂O has the highest boiling point due to hydrogen bonding, which is
significantly stronger than the dipole-dipole and London dispersion forces present in the
other hydrides (H₂S, H₂Se, H₂Te) .

, 7. Vapor pressure _________ with increasing temperature.

 A) Increases
 B) Decreases
 C) Remains constant
 D) First increases, then decreases

Correct answer is A. As temperature increases, more molecules have enough kinetic
energy to escape the liquid phase, increasing vapor pressure .




8. Which of the following would have the lowest vapor pressure?

 A) CH₄
 B) C₄H₁₀
 C) C₆H₁₄
 D) C₈H₁₈

Correct answer is D. Larger molecules have stronger London dispersion forces, resulting in
lower vapor pressure. C₈H₁₈ is the largest molecule and therefore has the strongest
intermolecular forces .




9. In a phase diagram, the triple point is:

 A) The point where all three phases coexist
 B) The point where liquid and gas phases are indistinguishable
 C) The point where solid and liquid coexist
 D) The point where solid and gas coexist