CHEM 219 EXAM SCRIPT VERIFIED
QUESTIONS WITH ACCURATE ANSWERS
●● An exothermic reaction causes the surroundings to
Answer: An exothermic reaction transfers energy from the system to the
surroundings. That tells us the surroundings will get warmer.
●● nm to m
or
m to nm
Answer: 1 m / 10^9 nm
or
10^9 nm / 1 m
●● 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.
,●● A theory is another word for a(n) _________.
Answer: A theory or model is a well established explanation of a
phenomenon based on a series of facts and a body of evidence.
●● What is the definition of a natural law?
Answer: A scientific law summarizes an observable behavior.
●● The skeletal structure of a complex organic molecule is shown
below. Determine the number of sigma (σ) and pi (π) bonds in the
molecule.
Answer: Remember a single bond = 1 σ; a double bond = 1 σ + 1 π; a
triple bond = 1 σ + 2 π. This molecule contains 6 double bonds, so there
are 6σ and 6π. There are 28 single bonds, so there are 28 σ. This is a
total 34σ and 6π.
●● strontium phosphate
Answer: Sr₃(PO₄)₂
●● Which of the following statements is true?
Answer: One driving force in the vaporization of a liquid is an increase
in disorder (entropy). Gas molecules are more disordered than liquid
molecules. Adding a non-volatile solute to a liquid also increases the
disorder of the liquid molecules, so the difference in disorder between
the liquid and gas phases is not as great as with a pure substance.
, Therefore the tendency to vaporize is not as great for the solution as it is
for the pure liquid, resulting in a lower vapor pressure for the solution.
●● Which of the following aqueous solutions would have the highest
boiling point?
A) 1.0 m NaNO3
B) 1.0 m HF
C) 1.0 m C₆H₁₂O₆
D) 1.0 m CaCl2
Answer: The dissolved solute will raise the boiling point. The more
"things" that are dissolved (ions or molecules), the higher the boiling
point will be. The CaCl₂ will break up into one Ca²⁺ ion and two Cl⁻ ions
and there will be a concentration of 3.0 m of "things" in solution. The
other choices will have fewer "things" in solution and will raise the
boiling point less.
●● Which one of the following aqueous solutions would have the
highest freezing point?
A) 1.0 m NaNO3
B) 2.0 m CH3OH
C) 1.0 m C₆H₁₂O₆
D) 1.0 m CaCl2
QUESTIONS WITH ACCURATE ANSWERS
●● An exothermic reaction causes the surroundings to
Answer: An exothermic reaction transfers energy from the system to the
surroundings. That tells us the surroundings will get warmer.
●● nm to m
or
m to nm
Answer: 1 m / 10^9 nm
or
10^9 nm / 1 m
●● 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.
,●● A theory is another word for a(n) _________.
Answer: A theory or model is a well established explanation of a
phenomenon based on a series of facts and a body of evidence.
●● What is the definition of a natural law?
Answer: A scientific law summarizes an observable behavior.
●● The skeletal structure of a complex organic molecule is shown
below. Determine the number of sigma (σ) and pi (π) bonds in the
molecule.
Answer: Remember a single bond = 1 σ; a double bond = 1 σ + 1 π; a
triple bond = 1 σ + 2 π. This molecule contains 6 double bonds, so there
are 6σ and 6π. There are 28 single bonds, so there are 28 σ. This is a
total 34σ and 6π.
●● strontium phosphate
Answer: Sr₃(PO₄)₂
●● Which of the following statements is true?
Answer: One driving force in the vaporization of a liquid is an increase
in disorder (entropy). Gas molecules are more disordered than liquid
molecules. Adding a non-volatile solute to a liquid also increases the
disorder of the liquid molecules, so the difference in disorder between
the liquid and gas phases is not as great as with a pure substance.
, Therefore the tendency to vaporize is not as great for the solution as it is
for the pure liquid, resulting in a lower vapor pressure for the solution.
●● Which of the following aqueous solutions would have the highest
boiling point?
A) 1.0 m NaNO3
B) 1.0 m HF
C) 1.0 m C₆H₁₂O₆
D) 1.0 m CaCl2
Answer: The dissolved solute will raise the boiling point. The more
"things" that are dissolved (ions or molecules), the higher the boiling
point will be. The CaCl₂ will break up into one Ca²⁺ ion and two Cl⁻ ions
and there will be a concentration of 3.0 m of "things" in solution. The
other choices will have fewer "things" in solution and will raise the
boiling point less.
●● Which one of the following aqueous solutions would have the
highest freezing point?
A) 1.0 m NaNO3
B) 2.0 m CH3OH
C) 1.0 m C₆H₁₂O₆
D) 1.0 m CaCl2
