GENERAL CHEMISTRY 115
SECOND EXAM
FALL 2006
SECTION NO._______
NAME ____________________________
R = 0.0821 L atm/K mol
1 L atm/K mole = 101.3 J/K mole
1. Determine the volume of N2O5 liberated when 4.80 L of N2 is allowed to react with
10.20 L of O2 to form N2O5 at STP.
a) 10.20
b) 6.50
c) 4.80
d) 9.15
e) 1.86
f) 4.08
g) 2.40
h) 6.32
2. Calculate the number of moles of an ideal gas in a 830 mL container at a pressure of 650
mm Hg and a temperature of –15oC.
a) 0.235
b) 0.354
c) 33.5
d) 6.52
e) 0.0335
f) 3.54
g) 0.0652
h) 23.5
3. The average velocity of Cl2 molecules is 2.50 x 103 m/sec at a temperature of 250C,
therefore the average velocity of helium atoms is
a) 5.94 x 102 m/sec c) 1.05 x 104 m/sec
b) 1.41 x 102 m/sec d) 2.50 x 103 m/sec
e) 4.43 x 104 m/sec
f) 4.25 x 103 m/sec
g) 1.52 x 103 m/sec
h) 1.00 x 103 m/sec
4. In problem 3 above, the volume of the container was doubled keeping the temperature
constant. Therefore the average velocity of the helium molecules is
a) 1.41 x 102 m/sec
b) 5.94 x 102 m/sec
c) 1.00 x 103 m/sec e) 4.43 x 104 m/sec g) 1.25 x 103 m/sec
d) 5.00 x 103 m/sec f) 2.50 x 103 m/sec h) 1.05 x 104 m/sec
5. The molecular weight of a gas is 129 at 30oC and 740 mm Hg. Calculate its density.
a) 5.78 g/L
b) 1.06 g/L
c) 1.41 g/L
d) 3.90 g/L
e) 13 g/L
f) 51 g/L
g) 2.84 g/L
h) 5.05 g/L
6. A vessel is known to contain 8.0 g of helium and 40.0 g of argon at a temperature of
500 K and a total pressure of 6.00 atm. The partial pressure of argon is
a) 1.80 atm
b) 1.00 atm
c) 1.64 atm
d) 1.57 atm
e) 2.00 atm
f) 7.11 atm
g) 5.00 atm
h) 4.50 atm
7. A flask contains 4.80 g of a gas. The volume of the flask at a temperature of 10oC and
650 mmHg pressure is 520 mL. The molecular weight of the gas is
a) 106
b) 284
c) 251
d) 578
e) 560
f) 231
g) 129
h) 390
8. Calculate the final temperature of the water when 68 g of a metal at 98.0oC is added to
250 g of water at 30.0oC.
(heat capacity of H2O = 4.184 J/g oC, heat capacity of metal is 6.2 J/g deg)
a) 73.2 oC
b) 49.5 oC
c) 29.6 oC
d) 36.3 oC
e) 42.2 oC
f) 58.2 oC
g) 32.3 oC
h) 65.0 oC
9. Which of the following statements are true
A. The enthalpy of a reaction is -320 kJ and is therefore endothermic
B. The energy of a photon is inversely proportional to its wavelength.
C. The volume of an ideal gas is doubled when the temperature of the gas is heated from
30oC to 60oC at constant pressure.
D. The pressure of a gas is inversely proportional to its volume at constant temperature.
E. All gases in a five liter container at STP have the same the same number of
molecules.
a) A, B and D
b) A and D
c) A, B and D
d) A, B and C
10. Given the following data:
Substance
ZnS(s)
ZnO(s)
SO2(g)
e) A, B
f) B, D and E
g) B and D
h) A, B, C, D and E
Hfo ( kJ/mol)
-202.9
-348.0
-296.1
Calculate the value of Ho (in kJ) for the following readtion.
2ZnS (s) + 3O2 (g) ---------> 2ZnO (s) + 2SO2 (g)
a) –327.2
b) –189.2
c) –441.2
d) –882.4
11. Given the following data
Substance
CO2 (g)
H2O (l)
e) –1982
f) –150.0
g) –117.2
h) –3654
Hfo ( kJ/mol)
-393.5
-285.8
The value of Ho for the following reaction is -6535 kJ. What is the value of Hfo (in kJ/mol) for
C6H6(l)?
2C6H6(l) + 15O2 (g) ----------> 12CO2 (g) + 6H2O(l)
a) –92.8
b) 98.2
c) –98.2
d) 49.1
e) -49.1
f) -60
(g) 130
(h) –130
12. A gas is allowed to expand from 1.5 L to 12.5 L against a constant pressure of 6.5 atm.
How much heat is absorbed if the change in internal energy is 3672 J.
a) 26.75kJ
b) 10.92 kJ
c) 31.17 kJ
d) 12.90 kJ
e) 30.45 kJ
f) 6.69 kJ
g) 14.10 kJ
h) 3.57 kJ
Some equations: E = -RH(1/n2);
 = h/mu;
E = h
Some units: 1A = 1 x 10-10 m; h = 6.626 x 10-34 J s; c = 3.0 x 108 m/sec;
RH = 2.18 x 10-18 J
13. The ionization energy of the hydrogen atom is
a) 3.98 x 10-19 J
b) 1.88 x 10-19 J
c) 2.18 x 10-18 J
d) 2.34 x 10-15 J
e) 3.98 x 10-16 J
f) 1.33 x 10-27 J
g) 7.33 x 10-13 J
h) 1.88 x 10-16 J
14. What is the energy of electromagnetic radiation with a wavelength of 500 nm?
a) 3.98 x 10-19 J
b) 1.88 x 10-16 J
c) 1.88 x 10-19 J
d) 2.34 x 10-15 J
e) 3.98 x 10-16 J
f) 1.33 x 10-27 J
g) 7.33 x 10-13 J
h) 2.18 x 10-18 J
15. The electron configuration of element X is [Kr]5s24d3. This element is a (an)
a) main group element
b) chalcogen
c) halogen
d) transition metal
e) alkali metal
16. Determine the velocity of an electron that is required for electron diffraction. The wavelength
of light needed to observe diffraction is 0.10 nm.
The mass of an electron is 9.1 x 10-28 grams.
a) 1.88 x 109 m/sec
b) 3.98 x 106 m/sec
c) 2.18 x 108 m/sec
d) 3.98 x 109 m/sec
e) 7.28 x 109 m/sec g) 1.33 x 107 m/sec
f) 5.33 x 103 m/sec h) 7.28 x 106 m/sec
17. Determine the energy (in joules) of a photon of light emitted when an electron drops
from the fourth major energy level to the second major energy level.
a) 3.51 x 10-16 J
b) -4.35 x 10-19 J
c) -1.36 x 10-19 J
d) -2.18 x 10-19 J
e) -4.09 x 10-19 J
f) 4.94 x 10-17 J
g) 1.93 x 10-18 J
h) -5.45 x 10-19 J
18. Which statement is false?
a)
b)
c)
d)
e)
An electron that has n = 5 could be in an s, p, d, or f sublevel
An electron that has n = 2 cannot be in an d sublevel
If an electron has ml = -2, it might be in a p subshell but not in an s sublevel
If an electron has the quantum number l = 3, the only possible values of ml are 0, 1 and -1.
If an electron has the quantum number n = 2, the electron could be in a p sublevel.
19. Arrange the following elements in order of decreasing atomic radii.
Pb, P, Cl, F, Si
a) Cl > F > Pb > Si > P
b) Pb > Si > P > F > Cl
c) Pb > Si > P > Cl > F
d) Pb > Cl > P > Si > F
e) Cl > Pb > P > Si > F
f) Pb > Cl > Si > P > F
20. Write the electron configurations for each of the following.
a)
25Mn
____________________________
c) 9F _______________________
b)
19K
_____________________________
d) 17Cl _________________________
22. The ionization energy (the energy required to just remove an electron from an atom) for the
hydrogen atom in kJ/mole can be calculated using the Rydberg equation which allows you to
calculate the energy states of the electron in one atom. Use this equation to estimate the
ionization energy for lithium in kJ/mole. The experimental value is greater.
a) 1546
b) 2655
c) 410
d) 328
e) 2576
f) 1312
g) 258
h) 698
21. Write down four ions that are isoelectronic with Kr.
a._________ b. _________ c. ____________ d. ___________
23. Which set of quantum numbers are a correct set? (n, l, ml, ms)
a) 1, 2, 3, +1/2 c) 1, 1, 0, +1/2
b) 1, 2, -3, +1/2d) 1, 0, 0, +1/2
e) 1, 1, 1, -1/2
f) 1, 3, 2, -1/2
g) 2, 2, 1, -1/2
h) 5, 4, -5, -1/2
24. Arrange the following elements in order of increasing first ionization energy?
a) Be < B < C < O < N
b) Be < C < B < N < O
c) O < Be < C < N < B
d) B < Be < C < O < N
25. Circle all of the basic oxides
K2O
NO2
CO2
Cs2O
SO2
Na2O
BaO
e) Be < B < C < N < O
f) Be < B < O < N < C