CHEM 219 MODULE 5 PRACTICE
EXAMINATION 2026 QUESTIONS WITH
ANSWERS GRADED A+
◍ Explain how bonds are formed between atoms from the perspective of
atomic orbital theory..
Answer: Atoms form bonds by overlapping individual atomic orbitals from
each atom to produce molecular (bonding) orbitals.
◍ Which of the following properties, in general, increase as we move left to
right across a period in the periodic table? 1. atomic radius 2. ionization
energy 3. metallic characterA) 1 only B) 2 only C) 3 only D) 1 and 2 only E)
2 and 3 only.
Answer: B) 2 only
◍ Diatomic element.
Answer: When an atom is more stable when bonded to another atom
◍ Avogadro's Law.
Answer: equal volumes of gases at the same temperature and pressure
contain equal numbers of molecules
◍ All will contribute equally. Because boiling point elevation is a colligative
property, it depends only on the concentration of solute, not the type of
solute..
Answer: Vapor pressure describes the tendency of a substance to change
from the liquid to the gas phase, so substances with weaker intermolecular
forces will have higher vapor pressures. A substance's boiling point is also
indicative of the strength of the intermolecular forces, with weaker
intermolecular forces resulting in lower boiling points. Because acetone has
the lowest boiling point of the options given, it has the weakest
, intermolecular forces, and will therefore have the highest vapor pressure.
◍ Raoul's Law.
Answer: a law stating that the partial pressure of a solvent over a solution,
Pa, is given by the vapor pressure of the pure solvent, POa, times the mole
fraction of a solvent in the solution, Xa: Pa = XaPOa
◍ Dalton's Law.
Answer: The total pressure of a mixture of gases is the sum of the individual
pressures (Ptotal=P1+P2+P3...)
◍ What is the maximum number of electrons that can have the quantum
numbers n = 3, ℓ = 2, mℓ = -2?.
Answer: The Pauli exclusion principle states that no two electrons in a given
atom can share the same set of four quantum numbers (n, ℓ, mℓ, ms). This
set of quantum numbers contains three quantum numbers, with the only
missing quantum number being ms, which can take on the values +½ and
-½. Therefore, this set of three quantum numbers represents a single atomic
orbital, which can contain two unique electrons: one with ms = +½ and one
with ms = -½.
◍ osmosis.
Answer: Osmosis is the movement of solvent molecules (often water)
through a semipermeable membrane from a less concentrated solution into a
more concentrated one resulting in similar concentrations on each side of the
membrane.
◍ Write the molecular formula for each of the compounds whose bond-line
formulae are given below..
Answer: a) C5H10b) C3H8Oc) C4H10O
◍ Isomer.
Answer: Molecules with the same molecular formula but a different
structure, and therefore a different shape.- constitutional or structural
isomers
◍ On a piece of scratch paper, write out structural formulae for all of the
, constitutional isomers possible for the MF C3H6F2. How many isomers are
possible for this formula?.
Answer: 4
◍ Anion.
Answer: Becomes negatively charged when it receives an electron
◍ Formal charge formula.
Answer: FC = group # of element - (dots + dashes)- dots = non-binding
electrons (lone pair or single unpaired electrons)- dashes = bonding
electrons
◍ At a particular temperature, the solubility of H₂ in water is 0.140 M when
the partial pressure is 1.20 atm. What partial pressure (in atm) of H₂ would
give a solubility of 4.95 M?.
Answer: 42.4 atmC = kP --> c12/c1 = p2/p1
◍ Cation.
Answer: Becomes positively charged when it loses an electron
◍ Given that water's freezing point is 0.00ºC and the freezing point depression
constant (Kf) is 1.86 ºC kg/mol, calculate the freezing point depression for
a 3.00 molal solution (moles/kg) of NaCl in water. Assume ideal behavior of
the ions..
Answer: The following solution may contain one or more values that are
different from the problem provided to you, however, the steps to solve the
problem are the same.ΔT = i × Kf × mi = number of dissociated ionsKf =
1.86°m = 3.00 molal solution
◍ For the following example of resonance:Which structure (a or b) represents
a "major" resonance contributor to the hybrid? Briefly explain why..
Answer: Structure "a" is a major contributor. All of the atoms have complete
valences and in addition, all of the atoms have a formal charge of zero (All
of the atoms are meeting their LDD bonding pattern).
◍ The boiling point of a liquid is the temperature at which its vapor pressure is
_______ the pressure of the gas above it..
EXAMINATION 2026 QUESTIONS WITH
ANSWERS GRADED A+
◍ Explain how bonds are formed between atoms from the perspective of
atomic orbital theory..
Answer: Atoms form bonds by overlapping individual atomic orbitals from
each atom to produce molecular (bonding) orbitals.
◍ Which of the following properties, in general, increase as we move left to
right across a period in the periodic table? 1. atomic radius 2. ionization
energy 3. metallic characterA) 1 only B) 2 only C) 3 only D) 1 and 2 only E)
2 and 3 only.
Answer: B) 2 only
◍ Diatomic element.
Answer: When an atom is more stable when bonded to another atom
◍ Avogadro's Law.
Answer: equal volumes of gases at the same temperature and pressure
contain equal numbers of molecules
◍ All will contribute equally. Because boiling point elevation is a colligative
property, it depends only on the concentration of solute, not the type of
solute..
Answer: Vapor pressure describes the tendency of a substance to change
from the liquid to the gas phase, so substances with weaker intermolecular
forces will have higher vapor pressures. A substance's boiling point is also
indicative of the strength of the intermolecular forces, with weaker
intermolecular forces resulting in lower boiling points. Because acetone has
the lowest boiling point of the options given, it has the weakest
, intermolecular forces, and will therefore have the highest vapor pressure.
◍ Raoul's Law.
Answer: a law stating that the partial pressure of a solvent over a solution,
Pa, is given by the vapor pressure of the pure solvent, POa, times the mole
fraction of a solvent in the solution, Xa: Pa = XaPOa
◍ Dalton's Law.
Answer: The total pressure of a mixture of gases is the sum of the individual
pressures (Ptotal=P1+P2+P3...)
◍ What is the maximum number of electrons that can have the quantum
numbers n = 3, ℓ = 2, mℓ = -2?.
Answer: The Pauli exclusion principle states that no two electrons in a given
atom can share the same set of four quantum numbers (n, ℓ, mℓ, ms). This
set of quantum numbers contains three quantum numbers, with the only
missing quantum number being ms, which can take on the values +½ and
-½. Therefore, this set of three quantum numbers represents a single atomic
orbital, which can contain two unique electrons: one with ms = +½ and one
with ms = -½.
◍ osmosis.
Answer: Osmosis is the movement of solvent molecules (often water)
through a semipermeable membrane from a less concentrated solution into a
more concentrated one resulting in similar concentrations on each side of the
membrane.
◍ Write the molecular formula for each of the compounds whose bond-line
formulae are given below..
Answer: a) C5H10b) C3H8Oc) C4H10O
◍ Isomer.
Answer: Molecules with the same molecular formula but a different
structure, and therefore a different shape.- constitutional or structural
isomers
◍ On a piece of scratch paper, write out structural formulae for all of the
, constitutional isomers possible for the MF C3H6F2. How many isomers are
possible for this formula?.
Answer: 4
◍ Anion.
Answer: Becomes negatively charged when it receives an electron
◍ Formal charge formula.
Answer: FC = group # of element - (dots + dashes)- dots = non-binding
electrons (lone pair or single unpaired electrons)- dashes = bonding
electrons
◍ At a particular temperature, the solubility of H₂ in water is 0.140 M when
the partial pressure is 1.20 atm. What partial pressure (in atm) of H₂ would
give a solubility of 4.95 M?.
Answer: 42.4 atmC = kP --> c12/c1 = p2/p1
◍ Cation.
Answer: Becomes positively charged when it loses an electron
◍ Given that water's freezing point is 0.00ºC and the freezing point depression
constant (Kf) is 1.86 ºC kg/mol, calculate the freezing point depression for
a 3.00 molal solution (moles/kg) of NaCl in water. Assume ideal behavior of
the ions..
Answer: The following solution may contain one or more values that are
different from the problem provided to you, however, the steps to solve the
problem are the same.ΔT = i × Kf × mi = number of dissociated ionsKf =
1.86°m = 3.00 molal solution
◍ For the following example of resonance:Which structure (a or b) represents
a "major" resonance contributor to the hybrid? Briefly explain why..
Answer: Structure "a" is a major contributor. All of the atoms have complete
valences and in addition, all of the atoms have a formal charge of zero (All
of the atoms are meeting their LDD bonding pattern).
◍ The boiling point of a liquid is the temperature at which its vapor pressure is
_______ the pressure of the gas above it..
