EXAM 1 – CHEM 1211 – SECTION A
NAME(1 point)___KEY Answers are highlighted_
100 points total
Dr. Gosnell
Sept. 16, 2005
Multiple Choice (33 questions; 3 points each
1. The boiling point of liquid helium is 4 K. What is this temperature in Celsius? Subtract 273
a) -294 ºC
b) -277 ºC
c) -269 ºC
d) -255 ºC
e) -169 ºC
2. Which one of the following is a homogeneous mixture? Looks uniform
a) baked beans
b) sugar dissolved in water
c) chocolate chip ice cream
d) chicken noodle soup
3. The density of acetic acid is 1.05 g/mL. What is the volume of 327 g of acetic acid?
d
mass
volume
a) 2.91  10-3 mL
volume 
327 g
mass

311ml
density 1.05 g / ml
b) 3.21  10-3 mL
c) 2.62  102 mL
d) 3.11  102 mL
e) 3.43  102 mL
4. What is the name of the element with the symbol B?
a) boron
b) beryllium
c) bismuth
d) bromine
e) barium
5. Which of the following is an extensive property? Depends on sample size
a) volume b) density c) melting point d) boiling point e) both melting and boiling point
6. Which one of the following is an example of physical change? No change in chemical identity
a) the evaporation of water
d) the tarnishing of silver
b) the rusting of iron
c) the combustion of hydrogen
e) both the rusting of iron and the tarnishing of silver
7. Two electronic balances are tested using a standard weight. The true mass of the standard is 1.3111 g.
The results of 5 individual measurements on each balance are recorded below.
Balance A
Balance B
0.8888 g
1.3110 g
0.9959 g
1.3109 g
Balance A has scattered data and
1.1182 g
1.3111 g
the average is not close to the standard.
1.0033 g
1.3110 g
Balance B has data that are close to
0.9938 g
1.3110 g
each other and close to the standard.
average mass =
1.0000 g
1.3110 g
Which statement best describes the results?
a) A: good precision, good accuracy. B: good precision, good accuracy.
b) A: good precision, good accuracy. B: poor precision, poor accuracy.
c) A: poor precision, good accuracy. B: good precision, good accuracy.
d) A: poor precision, poor accuracy. B: good precision, good accuracy.
e) A: poor precision, poor accuracy. B: good precision, poor accuracy.
8. A student determines the density of a bar of silver by measuring its dimensions (2.00 cm by 1.15 cm by
1.00 cm) and determining its mass (25.3 g). If the true density of silver is 10.5 g/cm3, what is the percent
error in the student’s measurement?
Volume = (length)x(width)x(heighth) = (2.00 cm)x(1.15cm)x(1.00cm)=2.30cm3
d
25.3g
mass

11g / cm 3
3
volume 2.30cm
%error 
exp exerimental  true
true
b) 3%
a) 1%
X 100 
11g / cm 3  10.5 g / cm 3
10.5 g / cm 3
d) 10%
c) 5%
x100  5%
9. An atomic mass unit (u) is defined as
a) the mass of one hydrogen-1 atom.
b) 1/8 the mass of one oxygen-16 atom.
c) 1/12 the mass of one carbon-12 atom.
d) 1.99  10-23 g.
e) the sum of the masses of one proton, one neutron, and one electron.
10. The wavelength of light emitted from a green laser pointer is 5.32  102 nm. What is the wavelength in
meters?
 1x10 9 m 
  5.32 x10 7 m
5.32 x10 2 nm
1
nm


-9
a) 5.32  10 m b) 5.32  10-7 m c) 5.32  10-5 m
d) 5.32  10-3 m
e) 5.32  10-1 m
11. Beta (β) particles are identical to ________.
a) neutrons
b) electrons
c) helium nuclei
d) light
e) protons
12. What is the correct answer to the following expression: (72.61 – 68.59)  18.76? Carry out the
subtraction operation first.
a) 7 × 101
b) 75
c) 75.4
d) 74.542
e) 75.5415
13. A typical volumetric flask holds a volume of 0.250 L. What is this volume in cubic centimeters?
 1000mL  1cm
Definition-1mL=1cm
0.250 L

 1L  1mL
a) 0.25 cm3
b) 2.50 cm3 c) 250 cm3
3
3

  250cm 3

d) 2.50 × 103 cm3
14. Which of the following postulates of Dalton’s atomic theory are now known to be incorrect?
1. Matter is made up of atoms.
2. All atoms of a given element are identical……..We now know about isotopes.
3. Atoms combine in whole number ratios to make compounds.
a) 1 only
b) 2 only
c) 3 only
d) 2 and 3
e) 1, 2, and 3
15. Which does not describe Tellurium (Te)?
a) metalloid
b) chalcogen
c) main group element
d) halogen
16. From the results of his gold foil experiment, Ernest Rutherford concluded that
a) electrons have a charge of –1.602  10-19 C.
b) atoms contain equal numbers of protons and electrons.
c) uranium ores emit a form of radiation that affect photographic plates.
d) alpha particles are helium nuclei.
e) atoms are composed of a small, dense nucleus surrounded by a cloud of electrons.
17. What is the correct name for PF5? Two non-metals, use molecular naming rules.
a) phosphorus pentafluoride
b) phosphorus pentafluorine
c) phosphorus(V) fluoride
d) phosphorus fluorate
e) phosphorus fluoride
18. What is the atomic symbol for an element with 28 protons and 31 neutrons?
a)
59
28
Ni
b)
31
28
Ni
c)
59
31
Ga
d)
28
59
Pr
e)
31
3
Li
19. What is the correct formula for cobalt(III) oxide?
a) CoO
b) Co3O
c) Co3O2
d) Co2O3
e) CoO3
20. Isotopes of a given element have the same number of ________, but different numbers of ________ in
their nucleus.
a) neutrons, electrons
b) electrons, protons
c) protons, electrons
d) neutrons, protons
e) protons, neutrons
21. Calculate the number of moles in 39 g silicon.
 1mol 
  1.4mol
39 g 
 28.0855 g 
a) 9.1 × 10-4 mol b) 0.72 mol
c) 1.4 mol
d) 11 mol
e) 1.1  103 mol
22. An element consists of two isotopes. The abundance of one isotope is 95.72% and its atomic mass is
114.9041 u. The atomic mass of the second isotope is 112.9043 u. What is the average atomic mass of
the element?
AW  .9572x114.9041u   0.0428x112.9042u   114.8u
a) 113.9 u
b) 113.0 u
c) 113.9 u
d) 114.8 u
e) 115.1 u
23. The molar mass of silver is 107.9 g/mol. What is the mass of a single silver atom?
107.9 g / mol
massatom 
1.792 x10 22 g
6.02 x10 23 atoms / mol
a) 1.539 × 10-26 g
b) 1.792 × 10-22 g
c) 1.079 × 10-20 g
d) 1.901 × 10-18 g
24. Which three elements are likely to have similar chemical and physical properties? Same column
a) sodium, lithium, and potassium
b) sodium, magnesium, and aluminum
c) nitrogen, oxygen, and neon
d) nickel, copper, and zinc
e) uranium, plutonium, and americium
25. Which of the following formulas is not correct? Ba is 2+ and O is 2- so they form BaO
a) Al2(SO4)3
b) NaClO3
c) Ba2O3
d) Mg(NO3)2
e) KH2PO4
d) NaCH2O2
e) NaCHO
26. What is the correct formula for sodium acetate?
a) Na2CH3O
b) NaCH3CO2
c) NaCH3O
27. All of the following are named correctly EXCEPT Should be Iron(II) sulfate
a) NiCl2·6H2O; nickel(II) chloride hexahydrate.
c) TiBr4; titanium(IV) bromide.
e) FeSO4; iron(I) sulfate.
b) MnO2; manganese(IV) oxide.
d) AuI; gold(I) iodide.
28. Benzene, an organic solvent, has the empirical formula CH. If the molar mass of benzene is 78.11 g/mol,
what is the molecular formula of benzene?
molarmass
78.11g / mol

6
empiricalf ormulamass
13g / mol
a) C4H30
b) C5H18
This means the molecular formula is 6 times the empirical
c) C6H6
formula.
d)C7H8
29. What is the mass percent of chlorine in iron(II) chloride?
FeCl2
Formula weight = 126.7504 g/mol
%massCl 
a) 14.0%
masschlorine
2 x35.5g / mol
x100 
x100  55.9%
FW
126.7504 g / mol
b) 28.0%
c) 44.1%
d) 55.9%
e) 66.7%
30. What is the molar mass of cobalt(II) iodide hexahydrate? CoI26H2O
Add masses of 1 Co, 2 I, 12 H and 6 O
a) 212.8 g/mol
b) 293.9 g/mol
c) 312.7 g/mol
d) 420.8 g/mol
31. How many oxygen atoms are in 1.50 mol of SO3?
 3molO  6.02 x10 23 atomsO 

  2.7 x10 24 atomsO
1.50mol
1
molSO
1
molO

3 

a) 7.71 × 1021 atoms
d) 9.03  1023 atoms
b) 1.12  1022 atoms c) 3.01  1022 atoms
e) 2.71  1024 atoms
e) 465.1 g/mol
32. A 2.000 g sample of CoCl2·xH2O is dried in an oven. When the anhydrous salt is removed from the oven,
its mass is 1.565 g. What is the value of x?
Mass of water = mass before drying – mass after drying = 2.000 g – 1.565 g = 0.435 g water
Molar mass of water  18 g/mol
formula mass of anhydrous CoCl2 = 129.9 g/mol
 1mol 
0.012mol
molCoCl 2  1.565 g 
 129.9 g 
 1mol 
  .024mol
molH 2 0  0.435g 
 18 g 
molH 2 O 0.024

2
molCoCl2 0.012
a) 1
b) 2
c) 3
d) 4
e) 6
33. Toluene is composed of 91.25% C and 8.75% H. Determine the empirical formula for toluene.
A 100 g sample would have 91.25 g C and 8.75 g H. Find moles of each in 100 g sample.
 1mol 
  7.60molC
91.25 gC
12
.
011
g


ratio 
 1molH 
  8.68molH
8.75 gH 
1
.
0079
g


molH 8.68mol

 1.14
molC 7.60mol
Find matching ratio in the answer selections.
a) CH ratio =1 b) CH3 ratio = 3
c) C4H5 ratio =5/4=1.25
d) C7H8 ratio=8/7=1.14
BONUS POINT – 3 POINTS EACH
34. Which of the following statements are correct?
1. Metals generally lose electrons to become cations.
2. Nonmetals generally gain electrons to become anions.
3. Group 2A metals form ions with a 2+ charge.
a) 1 only
b) 2 only
c) 3 only
35. How many grams are in 0.0751 mol Br2?
a) 4.70 × 10-4 g
36.
b) 0.0833 g
d) 1,2, and 3
 159.8 g 
0.0751mol
  12.0 g
 1mol 
c) 2.13 g
d) 6.00 g
e) 12.0 g
What is the common name for NH3?
a) ammonia
b) nitrogen trihydride
c) trihydrogen nitride
d) ammonium ion