Chem1411 Tets1
Total Points 50
Answer all questions.
Pay attention to units and make the conversions where relevant.
Section I
1X15
1. Complete the following sentence. A scientific law is
A) a tentative explanation for a set of observations that can be tested by further experimentation.
B) a statement describing a relationship between phenomena that is always the same under the same
conditions.
C) a unifying principle that explains a body of facts and relations.
D) a model used to visualize the invisible.
2. Which one of the following is an example of a physical property?
A) dynamite explodes
D) ice floats on top of liquid water
B) meat rots if it is not refrigerated
E) a silver platter tarnishes
C)
gasoline burns
3. Complete the following chart, in order from left to right
Isotope Mass Number Protons
40
19
A)
40
Zr, 21 B)
19
K, 40
C)
21
K, 19
D)
40
K, 21
E)
Neutrons Electrons
19
38
Sr, 19
4. Convert 4.89 mm to µm.
A) 4.89 x 10-6 µm
B) 4.89 x 10-3 µm
C)
4.89 x 103 µm
D)
E)
4.89 x 106 µm
4.89 x 109 µm
5. Name the compound CrO3.
A) chromium oxide
B) chromium(II) oxide
C) chromium(III) trioxide
D)
E)
chromium(III) oxide
chromium(VI) oxide
6. There are two stable isotopes of chlorine: chlorine-35, with a mass of 34.968853 amu; and chlorine-37, with a
mass of 36.965903. Given that the average atomic mass of a chlorine atom is 35.45 amu, which of the
following statements is true?
35
Cl with very little 37
A) Chlorine contains almost exclusively 17
17 Cl.
35
17
Chlorine contains more
C)
Chlorine contains roughly equal amounts of
37
17
Cl than
37
17
B)
Cl.
35
17
Cl and
37
17
Cl.
35
17
D)
Chlorine contains more
Cl than Cl.
E)
Chlorine contains almost exclusively of
37
17
35
Cl, with very little 17
Cl.
7. If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in units of g/mol?
A) 2.28 × 102 g/mol
D) 2.17 × 102 g/mol
1
B) 1.71 × 10 g/mol
E) 6.02 x 1023 g/mol
–3
C)
4.38 × 10 g/mol
8. How many moles of C are in 1.22 moles of C6H12O6?
A) 7.32 moles C
D)
B) 87.9 moles C
E)
C)
1.22 moles C
14.7 moles C
2.44 moles C
9 What is the coefficient for O2 when the following combustion reaction of a fatty acid is properly balanced?
__ C18H36O2 + __ O2  __ CO2 + __ H2O
A) 1 B) 8 C) 9 D) 26 E) 27
10. Aluminum metal reacts with nitric acid to produce aluminum nitrate and hydrogen gas. Identify the
balanced reaction that describes this process.
A) Al + HNO3  AlNO3 + H2
D) Al + 3HNO3  Al(NO3)3 + H2
B) Al + HNO3  AlNO3 + H
E) 2Al + 6HNO3  2Al(NO3)3 + 3H2
C)
Al + 2HNO3  Al(NO3)2 + H2
11. When J. J. Thomson discovered the electron, what physical property of the electron did he measure?
A) its charge, e
D) its mass, m
B) its charge-to-mass ratio, e/m
E) its atomic number, Z
C)
its temperature, T
12. An anion is defined as
A) a charged atom or group of atoms with a net negative charge.
B) a stable atom.
C) a group of stable atoms.
D) an atom or group of atoms with a net positive charge.
13. What are the two different ions present in the compound NH4NO3?
A) NH4-, NO3+
D) NH43+, NO4+
B) NH4 , NO3
E) NH4+, NO3C)
N3-, H+, O214. Which is the formula for lead(IV) chloride?
A) Pb4Cl B) PbCl2 C) PbCl3
D) PbCl4 E) Pb2Cl4
15. The straight chain hydrocarbon that contains six carbon atoms is
A) propane B) butane C) pentane D) hexane E) heptane
Section II
Answer all questions.
Show all calculations where relevant
16. Give the structures of the sulfide ion, sulfate ion, and sulfite ion, in that order?
17. Define the Law of conservation of energy: 1X2
1X3
Use the following to answer questions 18-:
18a. Use the periodic table above to show where the alkali metals are located.
1
18b. Use the periodic table above to show where the halogen elements are located.
1
18c. Name one compound formed by the Alkali group element and a halogen element. What is the nature of this
compound, ionic or covalent? Why?
1X3
18d.Define the term molecule.
1
18e. Name 2 of the seven elements that naturally occur as diatomic molecules?
18f. Name 2 elements that naturally occur as liquid?
2
2
19. An archeologist finds a huge monolith in the desert. In order to estimate the weight of this object; he
estimates the dimensions of the monolith and removes some chips from the rock with his hammer,
collecting the following data:
3
dimensions of the monolith = 1.5 m × 5.2 m × 13 m
mass of rock chips = 41.73 g
volume of rock chips = 15.2 cm3
Determine the mass of the monolith in pounds, assuming it is of uniform composition. (1 lb = 453.6 g)
20. An investor paid market price for a chunk of gold that he was told was pure. The gold bar had a mass of 440
g, but was slightly irregular so an exact volume could not be calculated. The investor filled a large graduated
cylinder with water, immersed the chunk of gold, and observed an increase in the apparent volume of material
in the graduated cylinder of 25.0 mL. Pure gold has a density of 19.3 g/cm3. Did the investor get his money's
worth? Why or why not? 3
21. A cyclist averages 18.5 miles per hour. How many minutes will it take for him to complete a 125 kilometer
race? (1Mile = 1.61Km)
1
A) 252 min B) 652 min C) 420 min D) 1440 min E) 405 min
22. Ferrocene, Fe(C5H5)2(s), can be prepared by reacting 3.0 g of FeCl2(s) with an equal mass of
cyclopentadiene, C5H6(l), and an excess of KOH, as shown in the following reaction
FeCl2 + 2C5H6 + 2KOH  FeC10H10 + 2H2O
A. What is the limiting reagent in this procedure? Show how you arrived at your answer.
B. Based on your answer to part A, what mass of Fe(C5H5)2 could theoretically be formed?
1
2
C. A student who carried out this reaction obtained 2.7 g of ferrocene. What was the percent yield for this
reaction?
2
23a. What is the number of protons produced by H3PO4 ?
1
23b. Show the stepwise dissociation of this acid, making sure that the reactions are balanced and the state of
matter is mentioned in each step:
3X1
24. The percent composition by mass of tartaric acid is: 32.01% C, 4.03% H, and 63.96% O. Given that the
molecular mass of tartaric acid is 150 amu, determine its molecular formula.
3
25. Consider the reaction below and answer the following questions: 1X2
Cu + AgNO3  Cu(NO3 )2 + Ag
A. Balance this reaction.
B. How many grams of silver nitrate are necessary to react completely with 7.000 moles of copper?
Bonus Question :
10
Carbon and hydrogen form pure organic compounds. The 3 series of compounds formed by these two
elements are alkanes, alkenes and alkynes.
A.Alkanes: CH4, C2H6, C3H8, C4H10, etc.,…
The alkanes are typified by all single bonds between C and C and c and H.
B. Alkenes: C2H4, C3H6, C4H8, C5H10, etc.,…
The alkenes have one C& C double bond and all other C&C and C&H bonds are single
C. Alkynes: C2H2, C3H4, C4H6, C5H8. etc.,…
The alkynes have one C&C triple bond and all other C&C and C&H bonds are single.
1.Give the structure of one representative compound of each series:
{hint use your knowledge of the valences of C and H)
2.Give the empirical formula for each of the series using the CnHn notation:
Carbon also forms cyclic compound and retaining its valency of 4:
Predict the structure of C3H6 (Cyclical C backbone, and all single bonds), C6 H12(Cyclical C backbone, and all single bonds) and C6H6 Cyclical
C backbone, with alternating single and double bonds between the C atoms and C&H single bonds):