CHEM 104 MODULE 2

CHEM 104 MODULE 2 PRACTICE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES
2025


1. Which of the following is an exothermic process?
A. Boiling water
B. Melting ice
C. Condensation of steam
D. Evaporation of alcohol
Condensation releases heat to the surroundings, making it exothermic.



2. What is the sign of ΔH for an endothermic reaction?
A. Negative
B. Zero
C. Positive
D. Variable
Endothermic reactions absorb heat, so ΔH is positive.

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,3. Which color of visible light has the highest energy?
A. Red
B. Green
C. Violet
D. Yellow
Violet light has the shortest wavelength and therefore the highest energy.



4. The unit of energy commonly used in thermochemistry is:
A. gram
B. mole
C. joule
D. newton
Energy is measured in joules (J) in SI units.



5. What does the principal quantum number (n) determine?
A. Shape of orbital
B. Orientation of orbital
C. Size and energy level of orbital
D. Spin of electron
The principal quantum number indicates the main energy level and relative size.




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, 6. Which orbital is spherical in shape?
A. d
B. p
C. s
D. f
s orbitals are spherical in shape.



7. What is the value of the angular momentum quantum number (l) for a p-
orbital?
A. 0
B. 1
C. 2
D. 3
For p-orbitals, l = 1.



8. Which of the following is an allowed set of quantum numbers for an electron?
A. n = 2, l = 2, ml = 1, ms = +½
B. n = 3, l = 0, ml = 2, ms = –½
C. n = 4, l = 2, ml = 0, ms = +½
D. n = 1, l = 1, ml = 0, ms = –½
l must be less than n, and ml must be between –l and +l.



9. Which statement best describes Hund’s rule?
A. Electrons fill the lowest energy orbital first

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