Chemistry Exam Review
1. Generally, observed behavior that can be formulated into a statement, sometimes
mathematical in nature, is called a(n)
a. Observation
b. Measurement
c. Theory
d. Natural law
e. experiment
2. Convert 0.2974 m to mm
f. 297.4 mm
g. 2.974 x 10^-3 mm
h. 2.974 x 10^4 mm
i. 0.02974 mm
j. None of these
3. As part of the calibration of a new laboratory balance, a 1.000 g mass is weighted with the
following results:
TRIAL
MASS
1
1.201 +- 0.001
2
1.202 +- 0.001
3
1.200 +- 0.001
The balance is :
a) Both accurate and precise
b) Accurate but imprecise
c) Precise but inaccurate
d) Both inaccurate and imprecise
e) Accuracy and precision are impossible to determine with the available information
4. How many sig figs are there in the number 0.0006313?
a. 7
b. 3
c. 8
d. 4
e. 0
5. The pressure of the earth’s atmosphere at sea level is 14.7 lb/in ^2. What is the pressure when
expressed in g/m^2? (2.54cm - in, 2.205 lb - 1 kg)
a.
b.
c.
d.
e.
2.62 x 10^5 g/m^2
1.03 x 10^7 g/m^2
5.02 x 10^4 g/m^2
4.30 x 10^0 g/m^2
2.09 x 10^-5 g/m^2
6. An example of a pure substance is
a. Elements
b. Compounds
c. Pure water
d. Carbon dioxide
e. All of these
7. Which of the following pairs of compounds can be used to illustrate the law of multiple
proportions?
NH₄ and NH₄CL
a. ZnO₂ and ZnCl₂
b. H₂O and HCL
c. NO and NO₂
d. CH₄ and CO₂
8. Which one of the following statements about atomic structures is false?
a. An atom is mostly empty space
b. Almost all of the mass of the atom is concentrated in the nucleus
c. The protons and neutrons in the nucleus are very tightly packed
d. The number of protons and neutrons is always the same in the neutral atom
e. All of the above statements (A-D) are true.
9 - 18 missing
9. Bromine exists naturally as a mixture of bromine-79 and bromine-81 isotopes. An atom of
bromine-79 contains
Ans: 35 protons, 44 neutrons, and 35 electrons
10. Which of the following atomic symbols is incorrect
(A) 14/6 C
(B) 37/17 Cl
(C) 32/15 P
(D) 39/19 K
(E) 14/8 N
11. A species with 12 protons and 10 electrons is
Ans: Mg2+
12. Which of the following names is incorrect?
a. cobalt(II) chloride
b. magnesium oxide
c. aluminum (III) oxide
d. diphosphorus pentoxide
e. all are correct
13. The correct name for LiCl
Ans: lithium chloride
14. All of the following are in aqueous solution. Which is incorrectly named?
Ans: D (HCN Cyanic acid)
15. How many atoms (total) are there in one formula unit of Ca3(PO4)2?
Ans: 13
16. A hypothetical element consists of two isotopes of masses 86.95 amu and 88.95 amu with
abundances of 35.5% and 65%, respectively. What is the average atomic mass of this element
Ans: 88.2 amu
17. What is the mass of 4 atom(s) of copper in grams?
Ans: 4.22x10^-22g
18. A mixture of KCl and KNO3 is 44.20% potassium by mass. The percentage of KCl in the
mixture is closest to
Ans: 40%
19. What is the coefficient for water when the following equation is balanced?
As(OH)3(s) + H₂SO₄(aq) → As₂(SO₄) + H₂O(l)
a. 1
b. 2
c. 4
d. 6
e. 12
20. wPCL5 + xH2O → yPOCl3 + zHCL
a.
b.
c.
d.
e.
The above equation is properly balanced when:
W = 1, x = 2, y = 2, z = 4
W = 2, x = 2, y = 2, z = 2
W = 2, x = 2, y = 2, z = 1
W = 1, x = 1, y = 1, z = 2
None of these
21. How many grams of Ca(NO₃)₂ can be produced by reacting excess HNO₃ with 6.55 g of
Ca(OH)₂?
a. 7.25g
b. 14.5 g
c. 29.0g
d. 13.1 g
e. 6.55 g
22. When rubidium metal is exposed to air, two atoms of rubidium, Rb, combine with one atom
of oxygen. If 1.32 grams of rubidium is exposed to air, what will be the mass of the product in
grams?
a. 17.32g
b. 1.44g
c. 9.32g
d. 5.77g
e. 2.89g
23. All of the following reactions
2Al(s) + 3Br₂(l) → 2AlBr₃(s)
2Ag₂O(s) → 4Ag(s) + O₂(g)
CH₄(l) + 2O₂(g) → CO₂(g) + 2H₂O(g)
Can be classified as
a. Oxidation-reduction reaction
b. Combustion reaction
c. Precipitation reaction
d. A and B
e. A and C
24. When solutions of strontium chloride and sodium carbonate react, which of the following is a
spectator ion?
a. Strontium chloride
b. Chloride ion .
c. Sodium-ion .
d. Carbonate ion
e. Two of these
25. If all of the chloride in a 4.776-g sample of an unknown metal chloride is precipitated as
AgCl with a 70.90 mL of 0.2010 M AgNo₃, what is the percentage of chloride in the sample?
a. 50.52%
b. 10.58%
c. 1.425%
d. 9.454%
e. None of the above
26. What mass of NaOH is required to react exactly with 25.0 mL of 3.0 M H₂SO₄ ?
a. 3.0 g
b. 0.7g
c. 6.0g
d. 150g
e. None of these
27. Given the reaction:
2MnO₄⁻+ 5H₂O₂ + 6H⁻ → 2Mn²⁺ + 8H₂O +5O₂ ,
determine the number of electrons involved in this reaction.
a. 10
b. 8
c. 6
d. 4
e. 2
28. A physics experiment is conducted at a pressure of … kPa. What is this pressure in mmHg?
a. 18.4 mmHg
b. ..
c. 1.40 x …
d. 105 mmHg
e. 1.84 x 10 ^-2 mmHg
29. A gas sample is held at a constant pressure. The gas occupies 3.62 L of volume when the
temperature is 21.6 ℃. Determine the temperature at which the volume of the gas is 3.45 .
a. 309 K
b. 281 K
c. 20.6 K
d. 295 K
e. 554 K
30. What volume of H₂O(g) measured at STP is produced by the combustion of 3.85 g of natural
gas (CH₄) according to the following equation?
CH₄(g) + 2O₂(g) → CO₃(g) + 2H₂O(g)
a. 5.38 L
b. 10.8 L
c. 2.69 L
d. 11.7 L
e. 1.93 L
31. Given the equation:
2KClO₃(s) → 2KCl(s) + 3O₂(g)
A 3.00 g sample of KClO₃ is decomposed and the oxygen at 24.0 ℃ and 0.991 atm is collected.
What volume of oxygen gas will be collected assuming 100% yield?
a. 6.02 x 10^2 mL
b. 7.30 x 10^1 mL
c. 9.03 x 10^2 mL
d. 4.01 x 10^2 mL
e. None of these
32. Consider the reaction:
C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l); ΔH = -1.37 x 10^3 kJ
Consider the following propositions:
I.
The reaction is endothermic
II.
The reaction is exothermic
III.
The enthalpy term would be different if the water formed was gaseous.
Which of these propositions is (are) true?
a.
b.
c.
d.
e.
I
II
III
I, II
II, III
33. A 18.3 g piece of aluminum (which has a molar heat capacity of 24.03 J/ ℃ * mol) is heated
to 82.4 ℃ into a calorimeter containing water (specific heat capacity of water is 4.18 J/ ℃ * mol)
initially at 22.3 ℃. The final temperature of the water is 25.8 ℃. Ignoring significant figures,
calculate the mass of water in the calorimeter
a. 63.1 g
b.
c.
d.
e.
1.70 kg
1.91 g
923 g
None of these
34. What is the enthalpy change when 40.1 mL of 0.400 M sulfuric acid reacts with 19.5 mL of
0.133 M potassium hydroxide?
H₂SO₄(aq) + 2KOH(aq) → K₂SO4(aq) + 2H₂O(l) , ΔH° = - 111.6 kJ/ mol
a.
b.
c.
d.
e.
-0.145 kJ
-2.08 kJ
-1.79 kJ
-0.289 kJ
-112 kJ
35. At 25 ℃, the following heats of reaction are known: ΔH (kJ/mol)
2ClF + O₂ → C₂lO + F₂O : 167.4
2ClF₃ + 2O₂ → Cl₂O + 3F₂O : 341.4
2F₂ + O₂ → 2F₂O : -43.4
At the same temperature, calculate ΔH for the reaction: ClF + F₂ → ClF₃
a.
b.
c.
d.
e.
-217.5 kJ/mol
-130.2 kJ/mol
+217.5 kJ/mol
-108.7 kJ/mol
None of these
36. What is the wavelength of a photon of red light (in nm) whose frequency is 4.64 x 10^14 Hz?
a.
b.
c.
d.
e.
646 nm
1.55 x 10^5 nm
155 nm
464 nm
None of these
37. Which one of the following types of radiation has the shortest wavelength, the greatest
energy, and the highest frequency?
a. Ultraviolet radiation
b. Infrared radiation
c. Visible red light
d. Visible blue light
e. None, because short wavelength is associated with low energy and low frequency, not
high energy and high frequency.
38. Which of the following statements is false?
a.
b.
c.
d.
An orbital can accommodate at most two electrons.
The electron density at a point is proportional to ψ² at that point.
The spin quantum number of an electron must be either +½ or -½.
A 2p orbital is more penetration than a 2s: i.e., it has a higher electron density near the
nucleus and inside the charge cloud of a 1s orbital.
e. In the unusual order of filling, the 6s orbital is filled before the 4f orbital.
39. Which of the following electron configurations is correct?
a.
b.
c.
d.
e.
Ga: [Kr]4s²3d¹⁰4p¹
Mo: [Kr] 5s²4d⁵
Ca: [Ar]4s¹3d¹⁰
Br: [Kr] 4s²3d¹⁰4p⁷
Bi: [Xe]6s²4f¹⁴5d¹⁰6p³
40. Which of the following processes represents the ionization energy of bromine?
a.
b.
c.
d.
e.
Br(s) → Br⁺(g) + e⁻
Br(l) → Br⁺(g) + e⁻
Br(g) → Br⁺(g) + e⁻
Br(s) → Br⁺(s) + e⁻
Br₂(s) → Br₂⁺(g) + e⁻
41. For the elements Cs, F and Cl, the order of increasing electronegativity is
a.
b.
c.
d.
e.
F < Cl < Cs
Cs < Cl < F
Cl < Cs < F
F < Cs < Cl
None of these
42. When molten sulfur reacts with chlorine gas a vile-smelling orange liquid forms that is found
to have the empirical formula SCl. Which of the following could be the correct Lewis structure
for this compound
E.
43. Which of the following has an incomplete octet in its Lewis structure?
a. SO₂
b. ICl
c. CO₂
d. F₂
e. NO
44. How many resonance structures can be drawn for the molecule O₃?
a. 1
b. 2
c. 3
d. 4
e. 5
45. Which of the following types of molecules always has a dipole moment?
a. Linear molecules with two identical bonds
b. Tetrahedral molecules (four identical bonds equally spaced).
c. Trigonal pyramid molecules (three identical bonds).
d. Trigonal planar molecules (three identical bonds equally spaced).
e. None has a dipole moment.
46. NI₃
a. Pyramidal
b. Tetrahedral
c. Square planar
d. Octahedral
e. None of these
47. Using the following bond energies:
Bond: , Bond Energy:
C = C, 839
C - H, 413
O = O, 495
C = O, 799
O - H, 467
Estimate the heat of combustion for one mole of acetylene:
C₂H₂(g) + ½ O₂(g) → 2CO₂(g) + H₂O(g)
a. 1228 kJ
b. -1228 kJ
c. -447 kJ
d. +447 kJ
e. +365 kJ