Transcript Exam 1-3 Practice

Chemistry 107
Exam 1-3
Good Luck!
1.
Which of the following is NOT a
hypothesis?
a) Einstein is the greatest physicist that has
ever lived.
b) The Moon is made of green cheese.
c) The number of books in a backpack can
effect spinal issues.
d) Sugar free pop has no effect on a child with
attention deficit issues.
2. Which of the following is correct
for the material pictured?
a) a gaseous pure
substance
b) a liquid pure
substance
c) a gaseous mixture
d) a solid mixture
e) none of the above
3. Which of the
following has the
largest density?
a) a material that has a
mass of 10.0 g and a
volume of 2.00 L
b) a material that has a
mass of 5.00 g and a
volume of 10.0 cm3
c) a material that sinks in
ethanol but floats on
water
4. When reading a graduated cylinder, read the volume
at the bottom of the meniscus.
What volume of liquid is in the graduated cylinder?
a)
b)
c)
d)
e)
4 mL
5 mL
4.5 mL
4.6 mL
4.56 mL
5. A student measures the mass of a penny 4 times and
records the following data. What can be said about the
data if the actual mass of the penny is 2.4987 g?
a) The data is both
accurate and precise.
b) The data is neither
accurate nor precise.
c) The data is accurate, but
not precise.
d) The data is not
accurate, but it is
precise.
Trial
Number
Mass,
g
1
2.5104
2
2.5106
3
2.5102
4
2.5109
6. Which of the following
represents a chemical change?
a) Freezing water to make ice cubes
b) Dry ice evaporating at room
temperature
c) Toasting a piece of bread
d) Dissolving sugar in hot coffee
e) Crushing an aluminum can
7. Chlorine vaporizes at –34.4 C. What is this
temperature in degrees Fahrenheit?
a) –34.4 F
b) –29.9 F
c) 238.75 F
d) 307.55 F
e) 273.15 F
8. Which of the following would NOT be
considered an intensive property describing an
unknown sample?
a) It is a solid at 25 °C.
b) It has a density of 1.38 g/ cm3.
c) It melts at 62.0 °C.
d) It has a volume of 0.52 cm3.
e) It is shiny.
9. Calculate the following with the correct
number of significant figures.
(1.428  1.08)
 (2.83  0.360) 
0.288
a) 2
b) 1.4
c) 2.2
d) 1.36
e) 2.23
10. Determine the mass of 2.5 cups of water
if the density of water is 1.00 g/ cm3 and 1
cup = 240 mL.
a) 2.5 g
b) 6.0 x 102 g
c) 1.0 x 10–2 g
d) 2.4 x 102 g
e) 1.0 x 102 g
11. How many ounces of mercury are in 1.0
cubic meters of mercury? Hint: the density
of mercury is 13.55 g/cm3 and 1 ounce =
28.35g
a)
b)
c)
d)
e)
6.5 x 106 ounces
4.8 x 105 ounces
5.2 x 104 ounces
6.5 x 104 ounces
48 ounces
12. Which of the following is a pure
substance?
a) sweat
b) beef stew
c) coffee
d) apple juice
e) ice
13. Which of the following is a
heterogeneous mixture?
a) seawater
b) chicken soup
c) coffee
d) hydrogen peroxide
e) ice
14. Which of the following is a
chemical property?
a) squeezing oranges to make orange juice
b) melting butter for popcorn
c) separating sand from gravel
d) hydrogen peroxide decomposes to water
and oxygen
e) ozone is a gas at room temperature
15. Which of the following is not a
base unit?
a) meter
b) kilogram
c) liter
d) kelvin
e) ampere
16. Which of the following is true?
a) Energy is always conserved in a physical or
chemical change.
b) Systems with low potential energy tend to
change in a direction of high potential energy
spontaneously.
c) Thermal energy is a form of potential energy.
d) Objects with high potential energy are stable.
e) Chemical potential energy is a form of kinetic
energy.
17. Which of the following statements about
a carbon atom is correct according to the
plum-pudding atom model?
a) Anything can penetrate a
carbon atom.
b) The carbon atom only has a
positive charge.
c) The volume of the atom is
primarily from the positive
charge.
d) The carbon atom only has a
negative charge.
18. How many neutrons
are in 1000 atoms of
Cl-37?
a) 37
b) 37,000
c) 20
d) 20,000
e) cannot be determined
19. The mass spectrum of gallium, Ga, is shown below. The
atomic mass of Ga is 69.7 amu. Which of the following
statements is correct?
a) All Ga atoms weigh 69.7
amu.
b) The atomic mass of Ga is the
average of 68.9 and 71.9.
c) The atomic mass of Ga will be
closer to 69 than 71 because
there are more atoms that
weigh 68.9 amu.
Relative Abundance (%)
Gallium Mass Spectrum
70
68.9 amu, 60.1 %
60
50
71.9 amu, 39.9
%
40
30
20
10
0
67
68
69
70
Mass (amu)
71
72
20. Which of the following elements will have
properties most similar to Tin, Sn (at. no. 50)?
a) lead, Pb (82)
b) gallium, Ga (31)
c) zinc, Zn (30)
d) titanium, Ti (22)
e) arsenic, As (33)
21. Which weighs more, a pea or a marble?
a) Pea
b) Marble
22. Which has more atoms, 10.0 g
Mg or 10.0 g Ca?
a) Magnesium
b) Calcium
c) Both have the same
number of atoms.
23. Two samples of the same compound are compared:
Sample 1: 24.22 g carbon and 32.00 g oxygen
Sample 2: 36.22 g carbon and 48.00 g oxygen
This data shows which of the following:
a) The law of definite proportions
b) The law of multiple proportions
c) The law of conservation of mass
d) a and b only
e) a, b, and c
24. Which of the following
statements is true about ions?
a) An ion is the result of an atom gaining a neutron.
b) A positively charged ion is larger than the parent atom
because a proton was gained.
c) An ion is always smaller than the parent atom.
d) The gain or loss of an electron by an atom will result
in an ion.
e) None of the above
25. Boron has two naturally occurring isotopes:
B-10 with an isotopic mass of 10.013 amu
B-11 with an isotopic mass of 11.009 amu
Calculate the % abundance for each isotope if the
average atomic mass of boron is 10.81 amu.
a) 50.0 % B-10, 50.0 % B-11
b) 25.0 % B-10, 75.0 % B-11
c) 19.8 % B-10, 80.2 % B-11
d) 26.4 % B-10, 73.6 % B-11
e) Not enough information to determine
26. Calculate the mass in grams of one mole
of footballs if one football has a mass of 0.43
kg.
a)
b)
c)
d)
e)
430 g
1.4 g
2.6 x 1026 g
7.1 x 10-23 g
1.4 x 1027 g
27. Which of the following has the
largest mass?
a)
b)
c)
d)
e)
10.0 g Li
10.0 moles of Li
100 g Na
10.0 moles of K
100 g Rb
28. Which of the following elements
is an alkali earth metal?
a) Li
b) Fe
c) Ca
d) Ge
e) Pb
29. Which scientist confirmed that most of an
atom’s mass and all of its positive charge are
contained in a small core called the nucleus?
a) John Dalton
b) Joseph Proust
c) J. J. Thomson
d) Ernest
Rutherford
e) Robert Milliakn
30. Which of the following is false?
a) The mole can be used to specify
Avogadro’s number of anything.
b) Avogadro’s number is 6.122 x 1023
c) The mole is equal to the number of atoms
in exactly 12 grams of carbon-12.
d) The value of an elements molar mass in
grams per mole is numerically equal to
the element’s atomic mass.
31. There are two compounds of Ni and O. The green
colored oxide of nickel has a Ni:O mass ratio of 3.67:1 and
a Ni:O atom ratio of 1:1. The black colored oxide of nickel
has a Ni:O mass ratio of 2.45:1.
Which of the following is correct?
a) The two compounds have different formulas.
b) The two compounds have nickel ions with
different charges.
c) The Ni:O atom ratio of the black oxide is 2:3.
d) This is an example of the Law of Multiple
Proportions.
e) All of the above are correct.
32. A toy used to predict the weather had a picture containing CoCl2.
It worked on the following reversible reaction:
CoCl2 + 6 H2O  CoCl2 ∙ 6 H2O
Which of the following statements is correct?
a) The picture was red on sunny days and blue on rainy
days.
b) The picture was blue on sunny days and red on rainy
days.
33. Which of the following contains
the largest number of molecules?
a) 10.0 g CH4
b) 10.0 g C2H6
c) 10.0 g SO2
d) 10.0 g Xe
34. Which of the following contains
the largest mass percent hydrogen?
a) 10.0 g CH4
c) 10.0 g H2O
b) 10.0 g C2H6
d) 10.0 g H2S
35. Hydrocarbons are composed of just the
elements carbon and hydrogen. Which of the
following compounds has all single bonds?
a) naphthalene, C10H8
b) propane, C3H8
c) ethyne, C2H2
d) ethene, C2H4
36. Which of the following compounds
exhibits both ionic and covalent bonding?
a) SO2
b) CF4
c) NaCl
d) Na2SO4
e) P4O10
37. Determine which formula/ name
pair below is correct.
a) P2O5, phosphorus
pentoxide
b) H2O, dihydrogen monoxide
c) NaNO3, monosodium
nitrate
d) K2O, dipotassium
monoxide
e) Fe2O3, iron(II) oxide
38. Which sample represents the
greatest number of moles?
a) 44.01 g CO2
b) 1.0 moles C3H8
c) 6.022 x 1023 molecules
C4H10
d) 18.02 g H2O
e) All of the samples have
the same number of moles.
39. Calculate the number of carbon atoms in
25.0 grams of isopropyl alcohol (C3H8O).
a) 1.25 C atoms
b) 15.0 C atoms
c) 2.51 x 1023 C atoms
d) 7.52 x 1023 C atoms
e)2.07 x 10–24 C atoms
40. An unknown compound contains the
following percents by mass: C: 60.86%, H:
5.83%, O: 23.16%, and N: 10.14%. Find the
empirical formula.
a) C6H8O2N2
b) C7H8O2N
c) C6H8O2N
d) C8H8O2N
e) C8H8ON
41. What is the empirical formula of a
compound containing C, H, and O if
combustion of 3.69 g of the compound
yields 5.40 g of CO2 and 2.22 g of H2O?
a) CH3O
b) C2H3O
c) CHO
d) C2H3O2
e) CH2O
42. What are the coefficients for the
decomposition of nitroglycerin?
__ C3H5N3O9  __ N2 + __ CO2 + __ H2O + __ O2
a) 2,3,6,2,1
b) 2,3,6,5,1
c) 4,6,12,10,12
d) 4,3,12,10,1
e) 4,6,12,10,1
43. What is the molecular mass of
calcium phosphate?
a) 310.18 g/mole
b) 230.02 g/mole
c) 324.99 g/mole
d) 135.05 g/mole
e) 214.18 g/mole
The Answers
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1A
2A
3C
4E
5D
6C
7B
8D
9C
10 B
11 B
12 E
13 B
14 D
15 C
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16 A
17 C
18 D
19 C
20 A
21 B
22 A
23 A
24 D
25 C (just for fun)
26 C
27 D
28 C
29 D
30 B
Answers Continued
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31 E
32 B
33 A
34 A
35 B
36 D
37 B
38 E
39 D
40 B
41 E
42 E
43 A