Download Exam 1 CEM 151 September 20, 2006

Exam 1
CEM 151
September 20, 2006
Name___________________
Section__________________
PID_____________________
Multiple choice (3 points each).
1. Give the formula for sodium acetate.
a. Na2CO3
b. NaHCO3
c. NaC6H6O6
d. NaC2H3O2
e. NaHCl
f. NaAsO4
2.
a.
b.
c.
d.
e.
f.
g.
What best describes the major result from Milikan’s oil drop experiment?
the structure of the atom
The mass of the proton
The mass of the neutron
The mass of the electron
The charge of the electron
d and e
a, b and c.
3.
a.
b.
c.
d.
e.
f.
g.
h.
What was the major conclusion of Rutherford’s gold foil experiment?
The mass of the electron
The nature of light
The structure of the atom
The charge of the electron
The mass of the electron.
The mass of the proton
d, e and f
a and d
4. Which group corresponds to the alkali earth metals?
a. 1
b. 2
c. 3
d. 4
e. 5
f. 6
g. 7
5. Which of the following are strong acids?
a. HC2H3O2
b. sodium carbonate
c. Sodium hydroxide
d. Perchloric acid.
e. Ammonia
f. a and c
g. a, c and e
h. a, b, c and e
6. Which of the following are strong bases?
a. Sodium hydroxide
b. Aluminum chloride.
c. Ammonia
d. Sodium bicarbonate
e. Sodium acetate.
f. HCl
g. a, b and c
h. a and b
i. a and f
Use the answers below to answer the next set of questions.
a. NaC2H3O2
b. NaClO3
c. NaClO4
d. NaNO3
e. NaClOf. Na2CO3
g. Na2SO4
h. Na3PO4
i. NO2j. NaHSO3
Give the correct formula for the following:
7. Sodium perchlorate
c
8. Sodium carbonate
f
9. Sodium bisulfite
j
10. Sodium nitrate
d
11. Sodium sulfate
g
12. Sodium chlorate
b
13. Sodium phosphate
h
14. Sodium hypochlorite
e
15. An element cannot ____________
a. be part of a homogeneous mixture
b. be part of a heterogeneous mixture
c. be separated into other substances by chemical means
d. interact with other elements to form compounds
e. be a pure substance.
16. Of the objects below, which is the most dense?
a. an object with a volume of 2.5 L and a mass of 12.5 kg
b. an object with a volume 139 mL and a mass of 93 g.
c. an object with a volume 0.00212 m3 and a mass of 4.33x104 mg
d. an object with a volume of 3.91x10-24 nm3 and a mass of 7.93x103 g
e. an object with a volume of 13 dm3 and a mass of 1.29x103
17. Which reside in the nucleus of atoms?
a. protons
b. electrons
c. neutrons
d. spartons
e. wolvons
f. None of the above
f. a, b and c
g. all of the above
h. a and c
i. d and e
18. Which pair of atoms is a pair of isotopes of the same element?
a. 146 X 147 X
b. 146 X 126 X
c. 179 X 178 X
19 19
d. 10
X 9X
e. 146 X 147 X
20 21
f . 10
X 11X
g. a, c, d, e
!
19. Which of the following are nonmetals
a. Sodium
b. Oxygen
c. Chlorine
d. Tin
e. Magnesium
f. Sulfur
g. a, b, c and f
h. b, c and f
i. b and f
20. Which represents the net ionic equation for the reaction of sodium hydroxide with
perchloric acid.
a. NaOH + HClO4 -----> NaClO4 + H2O
b. NaOH + HClO3 -----> NaClO3 + H2O
c. OH- + H+ ------> H2O
d. a and c
e. Na+ + OH- + H+ + ClO4- ------> Na+ + ClO4- + OH- + H+
f. a, c and e
g. b and c
Work the problems, show your work.
(10 points) 21. The concentration of carbon monoxide in a room is 50. µg/L. How many
grams of carbon monoxide are there in the room of dimensions 40. m x 50. m x 50. m?
V = (40 m)(50 m)(50 m)=100,000 m3(10 dm/m)3=1.0 x 108 dm3= 1.0x108 L
50x10-6 g/L(1.0x108L) = 5000
g.
(10 points) 22. If a car burning (by a standard combusion reaction) pure octane (C8H18),
gets 18 miles/gallon and travels 225 miles, how many kilograms of CO2 will it produce?
d = 0.800 g/mL
C8H18 + 12.5O2 ------> 8CO2 + 9H2O
225 miles/(18 mi/gal) = 12.5 gal(3.74 L/gal)(1000 mL/L)(.800 g/mL) = 37400 g octane
37400 g octane(1 mol?114 g) = 328 moles octane
328 moles octane(8 moles CO2/mol octane)(44 g/mol) = 115456 g = 120 kg CO2
(10 points) 23. The fizz produced by alka selzer is due to the reaction:
3NaHCO3(aq) + H3C6H5O7 ----- 3CO2 + 3H2O + Na3C6H5O7
How much carbon dioxide is produced if 10. grams of sodium bicarbonate and 10. grams
of citric acid are reacted together?
3NaHCO3(aq) + H3C6H5O7 ----- 3CO2 + 3H2O + Na3C6H5O7
10 g
10 g
?
?
?
MW:
84 g/mol
192
44
18
212
0.119 mol
.052 mol
0.156
.052
0.119
.0397
0.119
10 g
0.119 mol(44 g/mol) =
5.2 g.
(10 points) 24. Determine the empirical formula of the compound with the composition:
55.3% K, 14.6% P and 30.1% O.
Assume 100 g:
Moles K: 55.3 g/(39.09 g/mol) = 1.414/.471 = 3.0
Moles P: 14.6 g/(30.973 g/mol) = 0.471/.471 = 1
Moles: O: 30.1 g (16.00 g/mol) = 1.87/.471 = 4.0
K3PO4