Chapter 1-7 Exam Dr. Myton Spring 1999

Brady & Holum

 

 

____ 1. A piece of gold of mass 25.0 g at 88.0oC was placed in a calorimeter that contained 75.0 g of water at 25.00oC. If the temperature of the water rose to 25.70oC, what is the specific heat capacity of gold? The specific heat capacity of water is 4.184 J · (oC)–1 · g–1.

a) 0.14 J · (oC)–1 · g–1 d) 4.2 J · (oC)–1 · g–1

b) 5.2 J · (oC)–1 · g–1 e) 0.10 J · (oC)–1 · g–1

c) 0.35 J · (oC)–1 · g–1

 

 

____ 2. When benzene vapor condenses at constant pressure, the sign of the enthalpy change for the process

a) cannot be determined. d) depends on the container volume.

b) is positive. e) depends on the temperature.

c) is negative.

 

 

____ 3. When 5.00 g of methane, CH4(g) (Molar mass = 16.04 g/mol), is burned in a calorimeter with a heat capacity of 66.0 kJ · K–1, the temperature of the calorimeter assembly rises by 4.21 K. What is the standard enthalpy of combustion of methane?

a) –278 kJ · mol–1 b) –1389 kJ · mol–1 c) –1254 kJ · mol–1 d) –889 kJ · mol–1 e) –86.8 kJ · mol–1

 

 

____ 4. The standard reaction enthalpy for

2PCl3(g) ® 2P(s) + 3Cl2(g)

a) +2 DHfo[P(s)] + 3 DHfo[Cl2(g)] d) –DHfo[PCl3(g)]

b) +2 DHfo[PCl3(g)] e) +DHfo[PCl3(g)]

c) –2 DHfo[PCl3(g)]

 

 

____ 5. Calculate the reaction enthalpy for the decomposition of hydrogen peroxide,

2H2O2(l) ® 2H2O(l) + O2(g)

from the data

H2(g) + O2(g) ® H2O2(l) DHo = –187.8 kJ

2H2(g) + O2(g) ® 2H2O(l) DHo = –571.6 kJ

a) –98.0 kJ b) +473.8 kJ c) –196.0 kJ d) –947.2 kJ e) –89.8 kJ

 

 

____ 6. If the standard enthalpy of combustion of ethanol, C2H5OH(l) (Molar mass = 46.07 g/mol), is –1368 kJ · mol–1, calculate the heat output if 500 g of ethanol is burned.

a) 6.85 × 102 kJ b) 14.8 × 103 kJ c) 31.5 × 103 kJ d) 16.9 × 103 kJ e) 16.9 kJ

 

 

____ 7. All of the following reactions or processes are endothermic except

a) combustion. b) vaporization. c) sublimation. d) melting. e) I2(s) ® I2(g)

 

 

____ 8. The reaction enthalpy for

2CO2(g) ® 2CO(g) + O2(g)

is +566.0 kJ. The standard enthalpy of formation of CO(g) is –110.5 kJ · mol–1. What is the standard enthalpy of formation of CO2(g)?

a) –172.5 kJ · mol–1 d) –393.5 kJ · mol–1

b) –676.5 kJ · mol–1 e) –787.0 kJ · mol–1

c) –338.3 kJ · mol–1

 

 

____ 9. Calculate the wavelength of green light of frequency 5.70 ´ 1014 Hz.

a) 1050 nm b) 349 nm c) 526 nm d) 570 nm e) 190 nm

 

 

____ 10. Calculate the energy per photon of infrared radiation of frequency 3.00 ´ 1014 Hz. Planck's constant is 6.63 ´ 10–34 J · s.

a) 4.52 ´ 1047 J b) 5.97 ´ 10–11 J c) 2.21 ´ 10–48 J d) 120 kJ e) 1.99 ´ 10–19 J

 

 

____ 11. Which of the following has the lowest frequency?

a) blue light b) infrared radiation c) green light d) ultraviolet radiation e) x-rays

 

 

____ 12. Calculate the frequency of a photon emitted by a hydrogen atom when an electron makes a transition from the fourth to the second principal quantum level.

[Â = 3.29 ´ 1015 Hz; h = 6.63 ´ 10–34 J · s]

a) 2.18 ´ 10–18 Hz b) 1.83 ´ 108 Hz c) 1.31 ´ 103 Hz d) 6.17 ´ 1014 Hz e) 2.99 ´ 103 Hz

 

 

____ 13. Which subshell can hold the greatest number of electrons?

a) 3p b) 4p c) 5p d) 4s e) 3d

 

 

____ 14. What is the ground-state electron configuration of a sulfur atom?

a) [Ne]3s23p2 b) [Ne]3s23p3 c) [Ne]3s23p1 d) [Ne]3s23p5 e) [Ne]3s23p4

 

 

____ 15. What is the electron configuration of the Fe3+ ion?

a) [Ar]3d54s1 b) [Ar]3d4 c) [Ar]3d44s1 d) [Ar]3d5 e) [Ar]3d34s2

 

 

____ 16. A certain ion has the ground-state electron configuration [Ar]3d10. The ion is likely

a) Cl– b) Cu+ c) Cu2+ d) Ga+ e) Ni2+

 

 

____ 17. Which of the following atoms has the largest radius?

a) aluminum b) carbon c) chlorine d) boron e) oxygen

 

 

____ 18. Arrange K, Mg, and S in order of increasing radii.

a) Mg < K < S b) K < Mg < S c) S < K < Mg d) Mg < S < K e) S < Mg < K

 

 

____ 19. Which of the following has the highest first ionization energy?

a) F b) N c) C d) Be e) Cl

 

 

____ 20. Which of the following processes, with all species in the gas phase, would require the most energy?

a) Ca ® Ca+ + e– d) Ca+ ® Ca2+ + e–

b) Ca2+ ® Ca3+ + e– e) Rb ® Rb+ + e–

c) Ca ® Ca2+ + 2e–

 

 

____ 21. How many dots should one place around the symbol for gallium, Ga, when writing the Lewis symbol for the atom?

a) 3 b) 2 c) 13 d) 8 e) 1

 

 

____ 22. How many lone pairs of electrons does the bromine atom possess in the Lewis structure of HBr?

a) 3 b) 2 c) 1 d) 6 e) 4

 

 

____ 23. The Lewis structure of the nitrite ion shows around the central nitrogen atom

a) 3 single-bonded oxygens and 1 lone pair of electrons.

b) 2 single-bonded oxygens and 2 lone pairs of electrons.

c) 2 double-bonded oxygens.

d) 2 single-bonded oxygens and 1 double-bonded oxygen.

e) 1 single-bonded oxygen, 1 double-bonded oxygen, and 1 lone pair of electrons.

 

 

____ 24. Resonance forms can be written for

a) NH3 b) H2O c) SO2 d) OF2 e) H2S

 

 

____ 25. For the Lewis structure below, the formal charges on N, C, and S, respectively, are

a) –1, 0, +1 b) –1, –1, +1 c) +2, –1, –2 d) 0, 0, –1 e) –1, 0, 0

 

 

____ 26. A Lewis structure that obeys the octet rule can be drawn for

a) XeF4 b) XeO2 c) XeF2 d) XeOF2 e) XeF3+

 

 

____ 27. 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.

 

 

____ 28. Consider the following reaction:

3NO2(g) + H2O(l) ® 2HNO3(l) + NO(g)

How many moles of nitric acid are produced starting from 5.00 moles of NO2(g) and excess water?

a) 10.0 mol b) 3.33 mol c) 0.300 mol d) 1.67 mol e) 7.50 mol

 

 

____ 29. Consider the following reaction:

2Fe3+(aq) + 2Hg(l) + 2Cl–(aq) ® 2Fe2+(aq) + Hg2Cl2(s)

In this reaction,

a) Hg(l) is the oxidizing agent. d) Fe3+(aq) is the reducing agent.

b) Hg(l) is reduced. e) Hg(l) is oxidized.

c) Fe3+(aq) is oxidized.

 

 

____ 30. How many nitrogen atoms are present in 3 moles of nitrogen gas, N2?

a) 3.61 × 1022 b) 1.81 × 1022 c) 1.81 × 1024 d) 1.20 × 1024 e) 3.61 × 1024

 

 

 

 

Answer Key -- s99 exam3 ch1-7

1. a 0.14 J · (oC)–1 · g–1

2. c is negative.

3. d –889 kJ · mol–1

4. c –2 DHfo[PCl3(g)]

5. c –196.0 kJ

6. b 14.8 × 103 kJ

7. a combustion.

8. d –393.5 kJ · mol–1

9. c 526 nm

10. e 1.99 ´ 10–19 J

11. b infrared radiation

12. d 6.17 ´ 1014 Hz

13. e 3d

14. e [Ne]3s23p4

15. d [Ar]3d5

16. b Cu+

17. a aluminum

18. e S < Mg < K

19. a F

20. b Ca2+ ® Ca3+ + e–

21. a 3

22. a 3

23. e 1 single-bonded oxygen, 1 double-bonded oxygen, and 1 lone pair of electrons.

24. c SO2

25. e –1, 0, 0

26. b XeO2

27. a a high ionization energy and a high electron affinity.

28. b 3.33 mol

29. e Hg(l) is oxidized.

30. e 3.61 × 1024