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Houston Community College System
Chemistry 1413
EXAM # 2
The Periodic Table of the Chemical Elements
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CHEM 1413 Exam #2
Name: __________________
Dr. Violeta Coarfa
Score:
Part I. Multiple choice questions. ( 3 points each)
Direction- Please write your correct choice in space provide.
1. In molecular compounds, ________ share electrons to form ________bonds.
A) metals, ionic
B) nonmetals, ionic
C) metals, shared
D) nonmetals, covalent
E) metals, cations
2. How many electrons will gallium gain or lose when it forms an ion?
A) lose 1
B) gain 1
C) lose 2
D) gain 2
E) none of the given answers
3. What is the symbol for the ion with 9 protons and 10 electrons?
B) F
A) F+
C) Ar +
D) K +
E) K 
4. What is the ionic charge of an ion with 18 protons and 16 electrons?
A) 1+
B) 2+
C) 3+
D) 2-
E) 3-
5. A molecular compound
A) has a net charge of zero.
B) has a net positive charge.
C) has a net negative charge.
D) contains only cations.
E) contains only anions.
6. Which one of the following compounds contains an ion with a 3+ charge?
A) LiBr
B) PbO
C) FeCl2
D) AgF
E) AlPO4
7. What is the correct formula for the phosphide ion?
A) P
B) P3- C) P3+ D) P- E) P+
8. The compound FeCl2 is named
A) iron chlorine.
D) monoiron dichloride.
B) iron dichloride.
E) ferric chloride
C) iron (II) chloride.
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9. A(n) ________ is the smallest neutral unit of two or more atoms held together by a covalent bond.
A) molecule
B) nucleus
C) ionic compound
D) formula E) unit
10. Double and triple bonds form because
A) the atoms involved have high electronegativities.
B) one of the atoms in the molecule has more than 8 valence electrons.
C) single covalent bonds do not give all of the atoms in the molecule eight valence electrons.
D) the ions involved have charges larger than one.
E) there is at least one hydrogen atom involved in the bond.
11. Which of the following compounds contains a polar covalent bond?
A) sodium chloride
B) oxygen gas
C) calcium oxide
12. The VSEPR theory allows us to determine the
A) charge on an ion.
B) shape of a molecule.
C) color of a compound.
D) bond type for a molecule.
E) formula for a compound.
13. When a cation is formed from a representative element
A) electrons are gained and the ion is larger.
B) electrons are gained and the ion is smaller.
C) electrons are lost and the ion is larger.
D) electrons are lost and the ion is smaller
E) the cation acquires a negative charge.
14. The boron trifluoride molecule is
A) a polar molecule with polar bonds.
B) a nonpolar molecule with polar bonds.
C) a nonpolar molecule with nonpolar bonds.
D) a polar molecule with nonpolar bonds.
E) a polar molecule with ionic bonds.
15. The shape of ammonia is
A) linear.
B) tetrahedral.
C) pyramidal.
D) bent
E) octagonal.
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D) water
E) argon gas
16. Which of the following would NOT be a physical change?
A) freezing water to make ice cubes
B) tearing a piece of aluminum foil
C) boiling water for soup
D) fermentation of grapes to make wine
E) melting gold to make jewelry
17. Which of the following correctly gives the best coefficients for the reaction below?
N 2 H 4  H 2 O2  N 2  H 2 O
A) 1, 1, 1, 1
B) 1, 2, 1, 4
C) 2, 4, 2, 8
D) 1, 4, 1, 4
E) 2, 4, 2, 4
18. In this reaction, what is the reduced element?
Zn  2HCl  ZnCl2  H 2
A) ClB) zinc chloride
C) H+
D) Zn
E) oxygen
19. How many moles of carbon atoms are there in 0.500 mole of C 2 H 6 ?
A) 0.500 mole
B) 1.00 mole
C) 3.00 moles
D) 6.02 1023 moles
E) 4.00 moles
20. In a ________ reaction, two or more elements or compounds form one product.
A) decomposition
D) double replacement
B) single replacement
E) combination
C) dehydration
21. One mole of particles of any substance contains how many particles?
A) 106
B) 3 1010
C) 3  1010
E) 6.02  1023
D) 6.02 1023
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22. 4.00 moles of sodium have a mass of
A) 4.60 g.
B) 11.0 g.
C) 23.0 g.
D) 44.0 g.
E) 92.0 g
23. Given the following equation, what is the correct form of the conversion factor needed to convert the
number of moles of O2 to the number of moles of Fe 2 O3 produced?
4Fe  3O2  2Fe2O3
A)
4moles Fe
3moles O 2
B)
4moles Fe
2moles Fe 2 O3
D)
2moles Fe 2 O3
4moles Fe
E)
2moles Fe 2 O3
3moles O 2
C)
3moles O 2
2moles Fe 2 O3
24. The volume of a gas with a pressure of 1.2 atm increases from 1.0 L to 4.0 L. What is the final pressure of
the gas, assuming constant temperature?
A) 1.2 atm
B) 0.30 atm
C) 3.3 atm
D) 4.8 atm
E) 1.0 atm
25. The force of gas particles against the walls of a container is called
A) pressure.
B) volume.
C) temperature.
D) quantity of gas.
E) density.
Part II. Show all your work for complete credit. ( 5 points each)
26)
a. What is the mass of 0.350 moles of calcium sulfide, CaS?
b. How many moles of potassium carbonate are in 15.0 g of potassium carbonate?
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For the following questions, 27 and 28, consider the following balanced equation.
Mg3 N2  6H2O  3Mg(OH)2  2NH3
27. When 1.5 moles of H 2 O react, how many grams of NH3 are produced?
28. How many grams of H 2 O are needed to produce 220 g of Mg(OH)2 ?
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29. Match the correct name of the polyatomic ions with the formulas given.
1) NO 3 
A) phosphate
2) CO 3 2 
B) hydroxide
3) SO 4 2
C) oxide
4) SO32
D) hydrogen carbonate
5) PO 43
E) sulfite
6) NO 2 
F) phosphate
7) HCO3
G) nitrite
8) HSO 4 
H) nitrate
9) OH 
I) hydrogen sulfate
J) sulfate
K) carbonite
L) carbonate
M) hydrogen sulfite
30. Indicate the type of bonding you would expect between the following elements.
1) Na and F
2) N and F
3) F and F
4) He and F
5) H and F
A) none
B) nonpolar covalent
C) polar covalent
D) ionic
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Part III. Bonus Questions. (3 points each). Show your work for full credit!
1. Consider the following reaction:
2H 2O2  2H 2O+O2
How many moles of oxygen gas can 30. g of hydrogen peroxide ( H2O2) produce, if decomposition is
complete?
2. Match the chemical name with the correct formula.
1) magnesium sulfate
A) Mg(HSO3 )2
2) magnesium hydrogen sulfate
3) magnesium sulfide
4) magnesium sulfite
B) MgSO3
C) MgS
D) Mg(HSO4 )2
5) magnesium hydrogen sulfite
E) MgSO4
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