Chem 1A Final Exam Review
Note: R = 0.08215 L×atm/mol×K
NA = 6.022 × 1023
R = 8.314 J/mo1A
h = 6.626×10-34 J
c = 3.0×108 m/s
Part 1
1. The number of protons, neutrons, and electrons, respectively, in a neutral atom of 121Sb (Z = 51) is
a) 121 protons, 70 neutrons, and 121 electrons
d) 70 protons, 51 neutrons, and 70 electrons
b) 51 protons, 51 neutrons, and 51 electrons
e) 51 protons, 121 neutrons, and 51 electrons
c) 51 protons, 70 neutrons, and 51 electrons
2.A heterogeneous mixture can be described as
a) one in which the composition of the mixture is the same throughout the sample.
b) a patchwork of aggregates of different substances.
c) being made up of a substance dissolved in water.
d) a solution like that obtained by dissolving table salt in water.
e) a mixture that has the same properties throughout the mixture.
3. At 25C, fluorine is a pale yellow gas with a density of 1.6 × 10-3 g/cm3. The melting point of F2(g) is
-220C and the boiling point is -183C, and the energy required to melt and boil fluorine is 0.51 and 6.5
kJ/mol, respectively. Fluorine is the most reactive element, and water actually bums in fluorine to form
HF(g). Which of the following is a chemical property of fluorine?
a) Fluorine is pale yellow in color.
b) Fluorine has a density of 1.6 × 10-3 g/cm3.
c) Fluorine boils at-1830C.
d) Fluorine reacts with water to give HF(g).
e) Fluorine liberates energy when it condenses.
4. The binary compound GaP is
a) gallium phosphate.
d) phosphorus gallide.
b) gallium phosphide.
e) gallium phosphite.
c) gallium phosphorus.
5. Which of the measured numbers below has the greatest number of significant figures?
a) 0.3100 b) 0.00310 c) 310. d) 3.1 × 10-4 e) 0.000310
6. How many moles of nitrogen atoms are contained in 10.62 g of nitrogen gas, N2?
a) 0.3790 mol
b) 2.638 mol
c) 0.7580 mol
d) 1.319 mol
e) 148.8 mol
7. How many grams of chlorine dioxide are needed to have 0.250 mol?
a) 22.4 g
b) 24.7 g
c) 16.9 g
d) 67.5 g
e) 24.5 g
8. The molar mass of fructose, the main sweetener in jams, is 180 g mol-1 and its empirical formula is CH2O.
What is its molecular formula?
a) C8H16O8 b) C6H1206
c) C6H10O4 d) C4H8O4
e) C3H6O3
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9. Calculate the molarity of a solution prepared by dissolving 2.073 g AgClO4 in enough water to prepare
75.00 mL of solution.
a) 1.333 × 10-4 M
b) 0.1333 M c) 9.999 × 10-3 M
d) 0.02764 M e) 0.74199 M
10. The combustion of butane, C 4H10(g), produces carbon dioxide and water vapor. In the balanced equation
for this reaction, what are the coefficients of butane, oxygen, carbon dioxide, and water, respectively?
a) 1, 6, 8, 10
b) 1, 6, 4, 5 c) 2, 13, 4, 10
d) 2, 13, 8, 10
e) 1, 13, 4, 5
11. When aqueous solutions of barium nitrate and ammonium sulfate are mixed, what are the "spectator ions"
in the reaction?
a) Ba2+ and SO42b) NH4+ and NO3c) Ba2+ and NO3d) SO42- and NO3e) NH4+ and SO4212.What type of reagent is required to convert NO2- to HNO2?
a) acid
b) base
c) reducing agent
d) oxidizing agent
e) neutralization reagent
13. Consider the following reaction:
IO3- (aq) + 2Tl+(aq) + 2Cl-(aq) + 6H+(aq) --> ICl2-(aq) + 2T13+(aq) + 3H2O(l) In this reaction,
a) IO3- (aq) undergoes oxidation.
d) C1-(aq) undergoes oxidation.
+
b) Tl (aq) is the oxidizing agent.
e) Tl+(aq) gains electrons.
c) IO3- (aq) undergoes reduction.
14. How many moles of carbon monoxide gas are produced when 2.88 moles of SnO2(s) react with excess
carbon according to the equation below?
SnO2(s) + 2C(s) --> Sn(s) + 2CO(g)
a) 14.32 mol b) 1.44 mol c) 5.76 mol d) 2.88 mol e) 11.5 mol
15. Rust, Fe 2 O3 (s), can be removed from porcelain according to the reaction below.
Fe2 O3 (s) + 6Na 2 C 2 O4 (aq) + 6HCl(aq) -> 2Na 3 Fe(C 2 O4 )3 (aq) + 6NaC1(aq) + 3H 2 O(l) How many moles
of rust can be removed by 500.0 mL of 2.84 M Na 2 C 2 O4 (aq)?
a) 0.236 mol b) 1.42 mol c) 0.500 mol d) 0.118 mol e) 8.52 mol
16. A 25.00-mL sample of HC1O4 (aq) was titrated to the stoichiometric point with 42.32 mL of 1.02 M
NaOH(aq). What is the mass of perchloric acid in the solution?
a) 1.73 g
b) 2.56 g
c) 4.34 g
d) 0.108 g
e) 0.0432 g
17. How many moles of carbon monoxide gas are produced from the reaction of 5.00 moles of Sn02(s)
with 8.00 moles of carbon according to the equation below?
SnO2 (s) + 2C(s) --> Sn(s) + 2CO(g)
a) 10.0 mol b) 16.0 mol c) 5.00 mol d) 4.00 mol e) 8.00 mol
18. Consider the following reaction:
6Na(1) + A1 2 O3 (s) -> 2Al(1) + 3Na 2 O(s)
How moles of Al(1) are produced from 5.00 g of each reactant?
a) 0.0490 mol
b) 0.217 mol c) 0.0980 mol
d) 0.0652 mol
e) 0.0725 mol
19. Ammonia burns in air as follows:
4NH3 (g) + 3O2 (g) --> 2N 2 (g) + 6H 2 O(g)
How many liters of N 2 (g) are formed by burning 4.50 L of ammonia and 4.50 L of oxygen with all
species at the same temperature and pressure?
a) 2.00 L
b) 3.00 L
c) 4.50 L
d) 2.25 L
e) 9.00 L
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20. What is the pressure of 20.0 g of oxygen gas in a container of volume 7.50 L at 39°C?
a) 1.60 atm b) 0.534 atm c) 4.27 atm d) 0.267 atm e) 2.13 atm
21. How many molecules of carbon dioxide gas occupy 1.00 mL at 0°C and 1.00 × 10-3 mmHg?
a) 3.54 × 1013 molecules d) 5.87 × 10 -11 molecules
b) 4.46 × 10 -8 molecules e) 6.02 × 1023 molecules
c) 2.69 × 10 16 molecules
22. An unknown sample of a gas has a density of 2.45 g/L at 1.50 atm and 25°C. Which of the following is
the gas?
a) Ar b) HCl
c) CO2
d) HF
e) N2
23. Which gaseous molecules (choose one species) effuse slowest?
a) SO2(g)
b) Ar(g)
c) NO(g)
d) N2(g)
e) CO2(g)
24. When benzene vapor condenses at constant pressure, the sign of the enthalpy change for the process
a) depends on the container volume.
d) cannot be determined.
b) depends on the temperature.
e) is negative.
c) is positive.
25.Calculate the reaction enthalpy for the decomposition of hydrogen peroxide,
2H2O2(l) ---> 2H2O(1) + O2(g)
from the data
H2(g) + O2(g) --> H2O2)
H = -187.8 kJ
2H2(g) + O2(g) --> 2H2O(1) H = -571.6 kJ
a) -89.8 kJ
b) +473.8 kJ c) -947.2 kJ d) -98.0 kJ
e) -196.0 kJ
26.Which thermochemical equation gives the value of the standard enthalpy of formation for XeO3(s)?
a) Xe2(g) + 3O2(g) --> 2Xe03
d) Xe(g) + 3O(g) --> XeO3(s)
b) 1/2Xe2(g) + 3O(g) --> XeO3(s)
e) Xe(g) + 3/2O(g) --> XeO3(s)
c) 1/2Xe(g) + 3/2O2(g) --> 1/2XeO3(s)
27. All of the following reactions or processes are endothermic except
a) combustion.
b) vaporization.
c) sublimation.
d) melting.
e) I2(s) --> I2(g)
28. If the standard enthalpy of formation of PH 3(g) is +5.4 kJ × mol-1, calculate the reaction enthalpy for
2PH3(g) -> 2P(s) + 3H2(g)
a) +5.4 kJ
b) +10.8 kJ c) -10.8 kJ
d) -2.7 kJ
e) -5.4 kJ
29. Calculate the wavelength of blue light of frequency 6.40 × 1014 Hz.
a) 214 nm
b) 311 nm
c) 640 nm
d) 936 nm
e) 468 nm
30. Calculate the energy per photon of blue light of frequency 6.40 × 1014 Hz.
Planck's constant is 6.63 × 10-34J-s.
a) 1.27 × 10-10 J
b) 256 kJ
c) 9.65 × 1047 J
d) 1.04 × 10-48 J
e) 4.24 × 10-19 J
31. Which of the following is a possible set of quantum numbers for a 4d-electron?
a) n=4,1=3,m E=2,ms,=1/2
d) n=4,1=2,m E = 0 , m s = - 1 / 2
b) n=4,1=l,m E =0, ms,=1/2
e) n=4,1=1,m E=-1,ms = -1/2
c) n = 4, l= 4, mE =-2, m s =1/2
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32. The atomic orbital for an electron in an atom with the quantum numbers:
n = 4, 1= 3, m E = 0, ms -1/2 is
a) 4s b) 4p c) 3d d) 4f e) 4d
33. A 4s-electron in the potassium atom is lower in energy than a 3d-electron due to
a) the relative sizes of the 4s- and 3d-orbital,.
d) the fact that there are five 3d-orbital,.
b) the shapes of the 3d-orbital,.
e) penetration and shielding.
c) a low ionization energy of potassium.
34. For the elements Be, B, N, and O, the first ionization energy increases in the order
a) Be<O<B<N b) Be<B<N<O c) B<Be<O<N d) B<Be<N<O e) Be<B<O <N
35. Metallic elements
a) have high ionization energies.
b) do not react with acids.
c) have low ionization energies.
d) form covalent halides.
e) have electron affinities higher than fluorine.
36. Which of the following has the largest lattice enthalpy?
a) MgCl2 (s) b) KCI(s)
c) LiCl(s)
d) NaCl(s)
e) AgCl(s)
37. How many lone pairs of electrons does the nitrogen atom possess in the Lewis structure of HCN?
a) 1
b) 4
c) 2
d) 0
e) 3
38. For the Lewis structure below, considering the atoms from left to right, the formal charges on N, N,
and O, respectively, are [N=N=0]
a) 0, +l, -1
b) -1, +1, 0 c) -1, 0, +1 d) -2, +1, +1
e) -2, 0, +2
39. How many lone pairs of electrons are there in the Lewis structure of XeF 4?
a) 14 b) 12 c) 2 d) 10 e) 4
40. Elements that have a high electronegativity have
a) a high ionization energy and a high electron affinity.
b) a low ionization energy and a high electron affinity.
c) a low ionization energy and a low electron affinity.
d) a high ionization energy and a low electron affinity.
e) an ionization energy that is approximately equal to its electron affinity.
41. For the following elements, predict the order of electronegativity, from lowest to highest:
O, As, Rb, Se, Ca
a) Rb<Ca<Se<As<O b) Rb<Ca<Se<O<As c) Rb<Ca<As<Se<O d ) Ca<Rb<As<Se<O e) Ca<Rb<Se<As<O
42. What is the molecular shape of C1O4 -?
a) tetrahedral
b) seesaw
c) square planar
d) T-shaped e) square pyramidal
43. What is the molecular shape of CIF 3?
a) T-shaped b) trigonal pyramidal
c) seesaw
d) trigonal planar
44. Estimate the O-C-O bond angle in peroxyacetylnitrate.
H3CC(O)N(O)OH ( the “(O)” refers to a double bonded oxygen)
a) 1200
b) < 1200 but > 109 0
c) 900
d) 1090
e) trigonal bipyramidal
e) < 1090 but >900
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45. Which of the following molecules is polar?
a) SF4 b) CC14 c) PCl3 d) BF3 e) SF6
46. Estimate the standard enthalpy of formation of methane from the following data:
HB (H2 ) = 436 kJ/mol
HB (C-H) = 412 kJ/mol
standard enthalpy of formation of C(g): 717 kJ/mol
a) +59 kJ/mol
b) -495 kJ/mol
c) +813 kJ/mol
d) -774 kJ/mol
e) +741 kJ; mol
47. The boiling point of O2 is higher than N 2 due to
a) London forces.
d) ion-ion forces.
b) hydrogen bonding.
e) ion-dipole forces.
c) dipole-dipole forces.
49. The boiling point of HF is higher than HCI due to
a) hydrogen bonding.
d) ion-ion forces.
b) dipole-dipole forces.
e) London forces.
c) ion-dipole forces.
50. For which of the following substances would hydrogen bonding be most important?
a) NH 3
b) HI
c) CH 4
d) H 2
e) GcH 4
Part II. Do all of the questions and show your work.
1. Sulfur reacts with bromine according to the reaction: S(s) + 2Br2 (l) --> SBr4
a) If 1.0 g of S(s) is mixed with 4.0 g of Br 2(l), which is the limiting reagent?
b) From the above mixture, how many grams of SBr 4 can be prepared?
2. A sample of a compound containing only the elements thallium, chlorine and oxygen was analyzed and
found to contain 67.27% Tl, 11.67% Cl, and 21.06% O.
Determine the empirical formula of the compound.
3.A sample of an unknown compound was vaporized to fill a 200. mL flask at 100. °C and a pressure of
765 Torr. The flask was weighed and found to contain 0.431 grams of the compound. Calculate the molar
mass of the compound.
4. a) Write a balanced chemical equation for the combustion of methanol (CH 3 OH).
b) )Calculate the enthalpy of combustion of methanol (in kJ/mom) from the following information.
Hf
CO2 (g) = 393.5
H2O(g) = 285.8
CH3OH(g) = 238.9
5. Write the Lewis structure of the compound SBr4.
a) Sketch and identify the three-dimensional structure of SBr 4. Include any distortions, if appropriate, and
indicate all bond angles.
b) Is this expected to be a polar molecule? (Note: the electronegativities are 2.6 for sulfur and 3.0 for
bromine). Explain briefly.
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6. The nitrite ion (NO2 - ) is an important polyatomic ion.
a) Write the Lewis structure of the nitrite ion.
b) Determine the formal charge for each atom.
c) Sketch the geometry of the nitrite ion. Indicate the bond angle and any distortion, i f appropriate.
d) Draw all of the possible resonance forms. Is any resonance form preferred? Explain briefly.
e) Indicate  and  bonds.
Part 3 Show all of your work
1. Nicotine, CwHxNy, has an molar mass of 162 g/mole. When a sample of mass 0.385 g was burned in oxygen,
1.072 g of carbon dioxide, 0.307 g of water, and 0.068 g of nitrogen (N2) were produced. Determine the molecular
formula of nicotine, and write the balanced equation for its combustion.
2. Provide correct names.
a. Na2SO4
b. Fe(IO4)3
c. (NH4)2 C03
d. Ba(MnO4)2
e. N203
f. HBrO
g. PtBr4
h. A12O3
i. Sc(OH)3
j. Ca(HCO3)2
3. A 1.735 gram sample is burned in a combustion calorimeter and the temperature of the
calorimeter increases from 19.26 0C to 30.580C. The calorimeter contains 525 grams of water and the bomb
has a heat capacity of 715 J/K. Calculate the heat evolved per gram of the compound combusted. The specific
heat of water is 4.184 J/g K.
4. The Ka's for H2CO3 are: K1= 4.5×10-7, K2= 4.7×10-11. Calculate the pH of the solution when 45.0 mL of
0.25 M KHC03 is mixed with: (INCLUDE NET-IONIC EQUATIONS)
a. 35.0mL 0.15 M HBr.
b. 50.0mL of 0.15 M KOH.
5. Calculate the molar solubility of Ag2CrO4, Ksp= 1.1x10-12, in: (INCLUDE NET-IONIC EQUATIONS)
a. 0.045 M K2CrO4
b. 0.0085 M AgNO3
6. Calculate Kb for CH3NH2 if a 0.095 M solution of the base has a pH of 11.86.
7. The pH of a 0.250 M Fe(NO3)3 solution is 1.44. Calculate Ka for the Fe+3 ion.
8. At 87°C, 22.0 moles of X(g), 33.0 moles of Y2(g), and 4.0 moles of X3Y5(g) are mixed in
a 80.0 liter container. At equilibrium, 10.0 moles of the product gas are present. Calculate KC a n d K p
6 X(g) + 5 Y2(g) --> 2 X3Y5(g)
9. How many grams of solid KF (molar mass = 58.1 g/mol) should be added to 1.00 L of 0.250 M HF to make a
buffer of pH = 3.143? (Ka for HF = 7.20  10-4)
a) 3.54 g
b) 3.98 g
c) 6.98 g
d) 10.1 g
e) 14.5 g
10. Only 1.06 g of Ca(NO3)2 will dissolve per liter of a solution that is buffered to a pH of 13.00. What is the
value of Ksp for Ca(OH)2? The molar mass of Ca(NO3)2 is 164.1 g/mol.
a)1.8  10-10 M b) 4.2  10-7 M c) 1.1  10-6 M d) 4.2  10-5 M e) 6.5  10-5 M
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