CHEM 101 WINTER 09-10 EXAM II
On the answer sheet (Scantron) write you name, student ID number, and recitation section number. Choose the
best (most correct) answer for each question and enter it on your answer sheet.
Avogadro’s Number: 6.022 × 1023 mol-1
Speed of Light: c = 3.00 x 108 mys-1
Planck’s Constant: h = 6.626 x 10-34 Jys
Rydberg Constant: R = 2.179 x 10-18 J
E = hc/λ = hυ
q = m c ΔT
1 cal = 4.184 J
1. Please choose the letter “a” as your answer for this question.
2. Which statement about energy is false?
a. Chemical reactions are processes that transfer energy.
b. Combustion reactions are exothermic processes.
c. The bond energy of foods and fuels is a type of potential energy.
d. Sublimation is an endothermic process.
e. Vaporization is an exothermic process.
3. Determine the incorrect relationship given below.
a. 80.0 cal/g = 312 J/g
b. 1 μJ = 1 × 10−6 J
c. 1000 cal = 1 kcal
d. 1000 J = 1 kJ
e. 44.0 kJ = 1.05 × 104 cal
4. The First Law of Thermodynamics states that:
a. Since energy cannot be created or destroyed, the total energy of the universe is constant.
b. The total entropy of the universe is increasing.
c. In any process, the total change in energy of a system, ΔE, is equal to the sum of the heat,
q, and the work, w, transferred betwen the system and the surroundings.
d. Samples with different temperatures that come in contact with one another will reach
thermal equilibrium.
e. Both “a” and “c” above are correct.
5. If heat is transferred to the system from the surroundings then
a. Δqsystem and Δqsurroundings are both negative
b. Δqsystem is positive and Δqsurroundings is negative
c. Δqsystem = Δqsurroundings = 0
d. Δqsystem is negative and Δqsurroundings is positive
e. Δqsystem and Δqsurroundings are both positive
6. A 25.0 kg sample of each substance below is cooled until each has released 25.0 kJ of energy. Which substance
will undergo the largest change in temperature?
a. water (specific heat = 4.184 J g−1 °C−1)
b. iron (specific heat = 0.451 J g−1 °C−1)
c. gold (specific heat = 0.128 J g−1 °C−1)
d. copper (specific heat = 0.385 J g−1 °C−1)
e. Not enough information to determine.
7. How much energy is required to raise the temperature of a 454.0 g sample of copper (specific heat = 0.385 J g−1
°C−1) from 60°C to 110°C?
a. 8.74 kJ
b. 8.74 x 103 μJ
c. 8.74 J
d. 8.74 x 103 kJ
e. None of the above answers is correct.
8. Solid sodium chloride, NaCl (s), has a molar heat capacity of 50.7 J mol−1 °C−1. What is the specific heat of sodium
chloride?
a. 58.5 J g−1 °C−1
b. 0.623 J g−1 °C−1
c. 117 J g−1 °C−1
d. 0.867 J g−1 °C−1
e. 5.30 × 103 J g−1 °C−1
9. Determine the final temperature of 900 g of ice, initially at –40°C, after the release of exactly 45 kJ of energy. The
specific heat of ice is 2.06 J g−1 °C−1.
a. +15.73°C
b. –55.73°C
c. –64.27°C
d. –15.73°C
e. +55.73°C
10. Which process is endothermic?
a. cream becoming ice cream
b. deposition of water vapor as frost
c. condensation of alcohol vapor into liquid alcohol
d. water turning into ice cubes
e. a frozen pond becoming a lake
11. Based on the following thermochemical equation, which statement is false?
NH3 (g)
NH3 (l)
H° = –23.4 kJ
a.
b.
c.
d.
e.
The energy of the surroundings increases.
The heat of vaporization for ammonia is known.
The equation represents an endothermic process.
The pressure for the process is known.
The thermochemical equation represents a change of physical state.
12. How much energy is released when 64.0 g of CH4 are burned in excess O2?
CH4(g) + 2O2(g)
CO2(g) + 2H2O(l)
H°= −890 kJ
a. −223 kJ
b. −890 kJ
c. −3560 kJ
d. +890 kJ
e. 3560 kJ
13. The complete combustion of 64.g of methanol produces 1276 kJ of heat. Determine the H° for the reaction.
CH3OH(l) + 3/2O2(g)
CO2(g) + 2H2O(g)
a. +638 kJ
b. −1.35 kJ
c. −638 kJ
d. +938 kJ
e. −938 kJ
14. Which of the following statements is true?
a. Breaking weak bonds and making a greater number of equally weak bonds is endothermic.
b. Breaking weak bonds and making an equal number of strong bonds is endothermic.
c. Breaking strong bonds and making a greater number of equally strong bonds is
endothermic.
d. Breaking strong bonds and making a greater number of equally strong bonds is
exothermic.
e. Breaking bonds is always exothermic.
15. Which statement regarding an orbital is true?
a. An orbital describes the location of the electron 90% of the time.
b. An electron shell consists of a collection of orbitals with the same principal quantum
number.
c. An orbital may be designated by the letters s, p, d, or f.
d. An orbital is three dimensional and may contain either one or two elecrons.
e. All of the above are true.
16. Which word or phrase least applies to the quantum number represented by the symbol n?
a. principal
b. shell
c. distance from nucleus
d. size
e. shape
17. Which statement is false?
a. Two electrons in the 3s orbital will have the opposite spin at the ground state.
b. The 2p orbitals have lower energy than the 3d orbitals.
c. The p orbitals occur in groups of 3.
d. The 2d orbitals hold up to 10 electrons.
e. The 3d orbitals hold more electrons than the 4p orbitals.
18. Which set of quantum numbers is not allowed?
a. n = 4, l = 3, ml = 0, ms = −1/2
b. n = 2, l = 1, ml = 1, ms = +1/2
c. n = 1, l = 0, ml = 0, ms = +1/2
d. n = 1, l = 3, ml = 0, ms = −1/2
e. n = 3, l = 1, ml = 0, ms = +1/2
19. What is the correct ground state electron configuration for phosphorus?
a. 1s22s22p63s23p6
b. 1s22s22p23s23p23d24s1
c. 1s22s1
d. 1s22s22p23s23p24s25s1
e. 1s22s22p63s23p3
20. Which element has the following ground state electron configuration?
1s22s22p63s23p5
a. Cl
b. In
c. Sr
d. Ni
e. Fe
21. Which of the following electron configurations is for an atom in an excited state?
a. 1s22s22p63s23p6
b. 1s22s22p63s23p5
c. [Kr]5s2
d. 1s22s22p6
e. 1s22s22p63s23p54s1
22. What is the electron configuration of N3–?
a. 1s22s22p2
b. 1s22s22p3
c. 1s22s22p1
d. 1s22s22p5
e. 1s22s22p6
23. Which one of the following has the electron configuration [Ne]3s23p6?
a. K+
b. Ca2+
c. Ar
d. Cl−
e. All of the above.
24. Atoms with no unpaired electrons are slightly repelled by a magnetic field and are called:
a. diamagnetic.
b. paramagnetic.
c. lanthanides.
d. ferromagnetic.
e. isoelectronic.
25. Which of these elements has the largest first ionization energy?
a. He
b. Sr
c. Ca
d. Xe
e. Cs
26. Which of these elements has an electron affinity greater than zero?
a. Br
b. Te
c. As
d. I
e. Kr