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CHEM 1405
Practice Final Exam (Chap. 1 - 12)
Name:_____________________
PART I – Multiple choice (2 points each)
DIRECTION- Please write your correct choice in the space provided.
1.
Which of the following is a basic step in the scientific method?
A) Perform an experiment and collect data
B) Analyze experimental data and propose a hypothesis
C) Test a hypothesis and state a theory or law
D) All of the above.
2.
Round off the following measurement to the three significant digits: 107.500g
A) 107g
B)
C)
108g
107.0g
D) 107.4
3.
Add 7.77g to 51.665g and round off the sum to the proper significant digits
A) 59.0g
B) 59.4g
C) 59.43g
D) 59.44g
4.
Express 0.000000000000000000000000000000010 as an exponential number.
A) 1.0 x 10
-10
B) 1.0 x 10
-32
C) 1.0 x 10 -33
D) 1.0 x 10
32
5.
Which of the following is not a branch of chemistry?
A) Analytical Chemistry
B) Environmental Chemistry
C) Physical Chemistry
D) Biological chemistry
6.
Which of the following unit factors is derived from: 1 mile = 1760 yards?
A) 1 mile/ 1 yard
B) 1760 miles/ 1 yard
C) 1760 yards/ 1 mile
D) 1760 yard/ 1760 miles
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7.
The radius of tin atom is 1.41 x 10
-8 cm. What is the radius of the atom in nanometers?
1m = 10 9 nm, 1m = 10 2 cm
A) 1.41 x 10
-16
nm
B) 1.41 x 10
-10
nm
C) 1.41 x 10
-4
nm
D) 1.41 x 10
-1
nm
8.
A glass cylinder contains four separate liquid layers: mercury (d=13.6g/mL), chloroform (d = 1.49g/mL), acetic acid (d= 1.05g/mL), ether (d = 0.708g/mL).
If a marrble(d= 3.05g/mL) is added to the cylinder, where does it come to rest ?
A) On top of the mercury layer
B) On top of chloroform layer
C) On top of acetic acid layer
D) On the top of ether layer
9.
A 50.0g sample of solid aluminum releases 420.0 calories when cooled from 100.0
0
C to
60.0
0
C. What is the specific heat of the metal?
A) 0.168 cal/(g x
0
C)
B ) 0.210 cal/(g x 0 C)
C ) 0.840 cal/(g x
0
C)
D) 4.76 cal/(g x
0
C)
10.
Given that methanol freezes at -94
0
C, what is the freezing point temperature on the Kelvin scale?
A) -367K.
B) -179K
C) -94K
D) 179K
11.
Which of the following elements is an example of a semimetal?
A) H
B) C
C) Fe
D) Ge
12.
Use the periodic table and predict which of the following elements a liquid at 25
0
C is?
A) B
B) Ba
C) Be
D) Br
13.
How many neutrons are in the nucleus of one atom of oxygen-18?
A) 2
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B) 8
C) 10
D) 18
14.
What is the maximum number of electrons that can occupy a 4d sublevel?
A) 4
B) 4
C) 7
D) 10
15.
The original periodic law was based on which of the following?
A) Increasing atomic mass
B) Increasing atomic number
C) Increasing isotopic number
D) Increasing mass number.
16.
Predict the boiling point for argon given the boiling points of Krypton (-152
0
C) and
Xenon (-107
0
C)
A) -197
0
C
B) -130
0
C
C) -62
0
C
D) -45
0
C
17.
What is the core electron configuration for a titanium (II) ion, Ti
2+
?
A) (Ar)
B) (Ar) 4s
2
.
C) (Ar) 3d
2
.
D) (Ar) 4s
2
3d
2
.
18.
Aqueous HBr is classified as which of the following?
A) Binary ionic
B) Ternary ionic
C) Binary molecular
D) Binary acid.
19.
What is the formula for the ionic compound composed of bismuth ion, Bi
3+
, and CN
-
?
A) BiCN
B) BiCN
3
C) Bi
3
CN
D) Bi(CN)
3
.
20.
Which of the following is not evidence for a chemical reaction producing a gas?
A) An odor is detected
B) a color change is observed
C) a flaming splint is extinguished
D) a burning splint bursts into flames
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21.
What are the products from the following decomposition reaction?
Co
2
(CO
3
)
3(s)
→
A) Co and CO
2
B ) CoO and CO
2
C ) Co
2
O
3 and CO
2
D) CoO, H
2
O, and CO
2
22.
How many methane molecules, CH
4
, have a mass of 3.2g?
A) 1.20 x 10 23 molecules
B) 1.20 x 10
24 molecules
C) 1.93 x 10
24
molecules
D) 3.01 x 10 23 molecules
23.
If 1.00mol of krypton gas exerts a pressure of 1.00 atm at 100
0
C, what is the volume of the gas? (R = 0.0821atm.L/mol.K)
A) 2.20mL
B) 8.21 L
C) 12.2L
D) 30.6L
24.
How many valence electrons are in a bromine atom and a bromide ion?
A) 1 and 7, respectively
B) 1 and 8, respectively
C) 7 and 8, respectively
D) 7 and 10, respectively.
25.
Which of the following ions has the following electron configuration: 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
10
4p
6
?
A) I -
B) S
2-
C) K
+
D) Sr
2+
26.
If the electronegativity values for H, N, O, and P are 2.1, 3.0, 3.5, and 2.1, respectively, which of the following is a nonpolar covalent molecule?
A) water, H
2
O
B) Laughing gas, N
2
O
C) phosphine, PH
3
D) ammonia, NH
3
.
27.
What is the strongest intermolecular force in a liquid containing polar molecule?
A) Covalent bond
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B) Ionic bond
C) Permanent dipole forces
D) Temporary dipole forces
28.
What are the products from the complete combustion of a hydrocarbon?
A) Carbon dioxide and water
B) Carbon monoxide and hydrogen
C) Carbon monoxide and water
D) Carbon dioxide and hydrogen
29.
What is the systematic name for for Ca(NO
3
)
2
.4H
2
O
A) Calcium nitrate dihydrate
B) Calcium nitrate tetrahydrate
C) Calcium nitrite dihydrate
D) Calcium nitrite tetrahydrate
30.
What is the strongest intermolecular force in a liquid having molecules with H-N bonds?
A) Dipole forces
B) Dispersion forces
C) Hydrogen bond
D) covalent Bond
PART II – Show your work (8 points for each question)
1.
Perform the following metric-metric conversions. a) 125 Gm to mm b) 255 mg to cg c) 1.85 mL to µL d) 8.15 x 10
4
ms to ks
2a.
A sample of fluorine gas occupies 855 mL at 710 mm Hg and 155
0
C. What is the mass of the sample? b.
A sample of krypton gas has a volume of 500.0mL at 225mm Hg and -125
0
C. Calculate the pressure in mm Hg if the gas occupies 220.0 ml at 100
0
C
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3. Refer to the periodic table and write the predicted electronic configuration for each of the following atoms.
(a) P (b) Ni
4 a. Draw the electron dot formula for nitrite ion, NO
2
-
. b. What is the overall, or electron domain, geometry of this molecule? c.
What is the molecular geometry of this molecule?
5a. If 25 moles of butane are combusted according to the following reaction, how many moles of water will be formed?
2 C
4
H
10
+ 13 O
2

8 CO
2
+ 10 H
2
O b . What is the mass of copper metal that can be prepared from the reaction of 1.25 g. of aluminum metal with excess CuSO4 according to the following reaction?
2 Al (s) + 3 CuSO
4
(aq)

3 Cu (s) + Al
2
(SO4)
3
(aq)
6. Dioxane is a common solvent for plastics. If the molar mass is 88g/mol and the percentage composition is 54.5% C, 9.15% H, and 36.3% O, what is the empirical and molecular formula of dioxane?
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7. Benzoyl peroxide is the active ingredient in a popular acne cream. Calculate the percentage composition of benzoyl peroxide, C
7
H
6
O
3
.
1. D 2. B 3. D 4. B 5. D 6.C 7.D 8.A 9. B 10. D
11. D 12. D 13. C 14. D 15. A 16. A 17. C 18. C 19. D 20. B
21. B 22. A 23. D 24. C 25. D 26. C 27. C 28. A 29. B 30. B
1 . a) 1250 mm b) 25.5 cg c) 1850 μL d) 0.0815 ks
2 . a) PV = nRT, n = PV / RT
= 0.02273 mol of
(0.02273 mol)(37.9968 g/mol) = 0.864 g of F
2
b) P
1
V
1
/T
1
= P
2
V
2
/ T
2
,
P
2
= 1288 mmHg
3 . a) P 1s
2
2s
2
2p
6
3s
2
3p
3 or [Ne] 3s
2
3p
3
b) Ni 1s
2
2s
2
2p
6
3s
2
3p
6
4s
2
3d
8 or [Ar] 4s
2
3d
8
4 . a) (two resonance forms; formal charge of one oxygen = –1)
b) Overall geometry = trigonal planar
c) Molecular geometry = bent
5 . a) 125 mol of H
2
O
b) mol of Al = 0.04633 mol, mol of Cu = 0.06949 mol, grams of Cu = 4.42 g
6 . Empirical formula = C
2
H
4
O
Molecular formula = C
4
H
8
O
2
7. Percent of carbon = 60.87% by mass
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