CHM 2045C Module 4 Part I Sample Chapter 9 Exam
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1. All of the following species are isoelectronic with argon EXCEPT

a.	Ca^2+.
b.	K^+.
c.	S^2-.
d.	Ga^3+.
e.	Cl^-.

2.The crystal lattice energy is represented by step(s)

a.	1.
b.	5.
c.	6.
d.	3, 4, 5.
e.	1, 2, 3, 4, 5.

3.The heat formation of sodium chloride can be found from step(s)

a.	1 + 2.
b.	2 + 4.
c.	5 - 6.
d.	3 + 4 + 5.
e.	1 + 2 + 3 + 4 + 5.

4. Which of the following compounds would be expected to have the largest crystal lattice energy?

a.	NaF
b.	NaCl
c.	NaBr
d.	NaI
e.	KI

5. _______ would be expected to have the highest melting point.

a.	KI
b.	KF
c.	NaCl
d.	NaF
e.	NaI

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6. All of the following represent stable positive ions EXCEPT

a.	Ba^2+.
b.	Ga^3+.
c.	Na^+.
d.	Ca^+.
e.	Pb^4+.

7. Which of the following atoms always violates the octet rule?

a.	F
b.	P
c.	S
d.	H
e.	Cl

8. In which of the following species is the octet rule violated by the central atom?

a.	CS2
b.	SF4
c.	CF3^-
d.	CH3^-
e.	NF3

9. The number of valence electrons in the nitrite ion, NO₂^-, is

a.	16.
b.	18.
c.	22.
d.	23.
e.	24.

10. The total number of valence electrons in the selenite ion, SeO₃^2-, is

a.	24.
b.	26.
c.	32.
d.	54.
e.	60.

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11. The total number of valence electrons in the perchlorate ion is

a.	24.
b.	26.
c.	28.
d.	30.
e.	32.

12.Which one of the following would have (a) Lewis structure(s) most like that of CO₃^2-?

a.	NO3^-
b.	NH3
c.	CH3^+
d.	SO4^2-
e.	SO3^2-

13. In the Lewis structure for the OF₂ molecule, the number of lone pairs of electrons around the central oxygen atom is

a.	0.
b.	1.
c.	2.
d.	3.
e.	4.

14. In the Lewis electron dot structure of hydrazine, N₂H₄, the total number of lone electron pairs around the two nitrogen atoms is

a.	0.
b.	1.
c.	2.
d.	3.
e.	4.

15. In the Lewis structure for the sulfite ion, SO₃^2-, the number of lone pairs of electrons around the central atom is

a.	0.
b.	1.
c.	2.
d.	3.
e.	4.

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16. The concept of resonance describes molecular structures

a.	that have several different geometrical arrangements.
b.	that have no suitable single Lewis electron-dot formula.
c.	that have electrons resonating.
d.	that are formed from hybridized orbitals.
e.	that have resonating structures.

Module 7 Questions 17 and 18

17. The bond energy of hydrogen bromide, HBr, is the change in enthalpy for the reaction

a.	1/2 H2(g) + 1/2 Br2(l) --> HBr(g)
b.	H2(g) + Br2(l) --> 2HBr(g)
c.	HBr(g) --> H(g) + Br(g)
d.	HBr(g) --> 1/2 H2(g) + Br(g)
e.	HBr(g) --> 1/2 H2(g) + 1/2 Br2(g)

18. Given the reactions

NF₃(g) à N(g) + 3F(g) DH = 841 kJ
FN = NF à 2N(g) + 2F(g) DH = 1033 kJ

the N=N bond energy in kJ/mol is

a.	192.
b.	280.
c.	473.
d.	560.
e.	1874.

Module 4 Part II Questions 19-25:

19. From a consideration of the following Lewis structure of sulfuric acid

the formal charge and oxidation number of sulfur are respectively

a.	+2 and +4.
b.	+2 and +6.
c.	0 and +4.
d.	0 and +6.
e.	-2 and +6.

20. In the ICl₂^- ion, the arrangement of the valence electrons about the central atom and the shape of the ion are, respectively,

a.	tetrahedral and planar.
b.	tetrahedral and linear.
c.	trigonal bipyramidal and planar.
d.	trigonal bipyramidal and linear.
e.	octahedral and planar.

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21. The electron pairs on N can be considered to be directed tetrahedrally in

a.	NH4^+.
b.	NO2^+.
c.	NO2^-.
d.	NO3^-.
e.	NO^+.

22. All of the following species are linear EXCEPT

a.	OSO.
b.	HCCH.
c.	NNO.
d.	OCO.
e.	HCN.

23. All of the following species would be expected to have a pyramidal shape EXCEPT

a.	NH3.
b.	ClO3^-.
c.	PCl3.
d.	SO3.
e.	PH3.

24. Which of the following molecules will have a molecular dipole moment?

a.	H2S
b.	CCl4
c.	HCCH
d.	C2H4
e.	CO2

25. All of the following molecules will have a molecular dipole moment EXCEPT

a.
b.
c.	PF5
d.	SF4
e.	SO2

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