PHYSICAL SCIENCE
982-021-06 (982-020-03) Section C2
Winter 2006
Test #2
April 24, 2006
Name
ID Number
MULTIPLE CHOICE: [2 MARKS EACH]
(Circle the letter of the one alternative that best completes the statement or answers the question)
1. Magnesium ions carry a 2+ charge, and chloride ions carry a 1- charge. What is the chemical formula for the
ionic compound magnesium chloride?
(a) MgCl
(b) Mg2Cl
(c) Mg2Cl2
(d) MgCl2
2. Phosphine is the simplest covalent compound containing only phosphorus, P, and hydrogen, H, where all atoms
obey the octet rule. What is its chemical formula?
(a) P2H3
(b) PH3
(c) H2P
(d) PH
3. The neon atom tends NOT to gain any additional electrons because
(a) its nuclear charge is not great enough.
(b) there is no more room available in its outermost occupied shell.
(c) of the repulsions they would experience with electrons in the same shell.
(d) that would result in a positive ion.
4. Water, H2O, and methane, CH4, have about the same mass and differ by only one type of atom. Why is the
boiling point of water so much higher than that of methane?
a) The oxygen of a water molecule has two lone pairs of electrons.
b) The electronegativity difference between oxygen and hydrogen is greater than the electronegativity difference
between carbon and hydrogen.
c) The water molecule is less symmetrical than is the methane molecule.
d) all of the above
5. Covalent and ionic bonds differ in that
(a) covalent bonds are much less common.
(b) ionic bonds do not involve the sharing of electrons.
(c) covalent bonds are more permanent.
(d) ionic bonds are electrical by nature.
6. Salts are made of elements found on opposite ends of the periodic table because elements on
(a) opposite ends of the periodic table have similar arrangements of electrons.
(b) the far left tend to form negative ions while those on the right tend to form positive ions.
(c) the far left tend to form positive ions while those on the right tend to form negative ions.
(d) Not true! Salts are generally made of elements found on the same side of the periodic table.
7. The atoms of materials that conduct electricity best tend to be held together by
(a) metallic bonds.
(b) covalent bonds.
(c) ionic bonds.
(d) polar covalent bonds.
8. When you set a pot of tap water on the stove to boil, you'll often see bubbles start to form well before boiling
temperature is ever reached. Explain this observation.
(a) These are dissolved salts heating up and escaping from the water.
(b) These initial bubbles are the gases that were dissolved in the water coming out of solution. The solubility of
gases in water decreases with increasing temperature.
(c) These bubbles are formed as the surrounding gases from the air dissolve into the water as it is heated.
(d) They are very minute pockets of water in the gaseous phase. When they get large enough, the water will boil as
this gas escapes.
9. How are ion-dipole attractions able to break apart the relatively strong ionic bond?
(a) The dipoles nullify the charges of the ions, which allows the ionic bond to fall apart.
(b) Dipoles can change polarity thus "fooling" the ions to be attracted to them instead of each other.
(c) Ion-dipole attractions cannot break the ionic bond.
(d) Many weaker ion-dipole attractions work together to pull apart the stronger ionic bond.
10. How many electrons are used to draw the electron-dot structure for acetylene (a covalent compound with the
formula, HCCH)?
(a) 8
(b) 5
(c) 12
(d) 10
11. At room temperature, chlorine is a gas and bromine is a liquid because
(a) in contrast to chlorine, the electrons of bromine are distributed over a larger volume making it easier for them to
congregate to one side. Bromine, therefore, has stronger induced dipole-induced dipole attractions.
(b) the chlorine molecule contains more atoms making it larger than bromine and thus having more induced dipoleinduced dipole attractions to hold it in a gaseous phase.
(c) the bromine molecule contains more atoms making it larger than chlorine and thus having more induced dipoleinduced dipole attractions to hold it in a liquid phase.
(d) chlorine is lighter than bromine and has more of a tendency to behave as a gas.
2
12. What is the mass of a single molecule of ammonia, NH3, in grams? (1 amu = 1.66 x 10-24 grams)
(a) 1.66 x 10-24 grams
(b) 2.83 x 10-23 grams
(c) 2.49 x 10-23 grams
(d) 6.65 x 10-24 grams
13. Energy is required to break apart a chemical bond to overcome
(a) the electrical forces of attraction.
(b) the nuclear forces of attraction.
(c) the gravitational forces of attraction.
(d) It is not! Energy is actually released when a bond is broken.
14. A refrigerator delays the spoilage of food by
(a) expanding the water found within microorganisms.
(b) killing microorganisms.
(c) slowing down the rate of chemical reactions within microorganisms.
(d) diminishing the supply of oxygen to microorganisms.
15. What is the formula mass of sulfur dioxide, SO2?
(a) about 64 amu.
(b) about 32 amu.
(c) about 60 amu.
(d) about 16 amu.
16. The carbon dioxide emitted by your gasoline powered vehicle of today, will
(a) one day end up at the bottom of the ocean.
(b) forever remain in our atmosphere.
(c) one day end up in plants and plant-eating animals.
(d) Both (a) and (c).
17. When the hydronium ion concentration, [H3O+], equals 100 moles per liter, what is the pH of the solution?
(a) pH = -2
(b) pH = 0
(c) pH = 2
(d) pH = 7
18. If, at room temperature, the hydroxide ion concentration, [OH–], equals 1 x 10-5 moles per liter, what is the pH
of the solution?
(a) 9
(b) 5
(c) 2
(d) 12
3
19. A buffer solution is a solution
(a) that remains at a constant pH value.
(b) that resists changes in pH.
(c) useful for polishing cars.
(d) that holds an average pH of 7.
20. Hydrogen chloride is added to a buffer solution of ammonia, NH3, and ammonium chloride, NH4Cl. What is
the effect on the concentration of ammonia? What is the effect on the concentration of ammonium chloride?
(a) HCl reacts with only the ammonia, so the concentration of the ammonium chloride increases and the
concentration of ammonia decreases.
(b) HCl reacts with both the ammonia and ammonium chloride, so the concentration of both increases.
(c) HCl reacts with only the ammonium chloride, so the concentration of the ammonium chloride decreases and the
concentration of ammonia increases.
(d) HCl reacts with both the ammonia and ammonium chloride, so the concentration of both decreases.
21. We measure the "acidity" of a solution by measuring the concentration of hydronium ions, H3O+. What does it
mean to say one has a "neutral" solution?
(a) There are no hydronium ions in this solution.
(b) The concentration of hydronium ions is small.
(c) The concentration of hydronium ions equals the concentration of hydroxide ions, OH–.
22. Which has more atoms: 64.058 g of sulfur dioxide, SO2 or 72.922 g of hydrogen chloride, HCl?
(a) 72.922 g of HCl and 64.058 g of SO2 have about the same number atoms.
(b) 72.922 g of HCl has more atoms than 64.058 g of SO2.
(c) 64.058 g of SO2 has more atoms than 72.922 g of HCl.
23. What are the formula masses of water, H2O; propane, C3H6; and 2-propanol, C3H8O?
(a) water: 18 amu. propene: 42 amu. 2-propanol: 62 amu,
(b) water: 18 amu. propene: 40 amu. 2-propanol: 58 amu.
(c) water: 18 amu. propene: 44 amu. 2-propanol: 64 amu.
(d) water: 18 amu. propene: 42 amu. 2-propanol: 60 amu.
24. How many grams of water, H2O, and propene, C3H6, can be formed from the reaction of 6.0 g of 2-propanol,
C3H8O?
C3H8O
2-Propanol
C3H6 +
Propene
H2O
Water
(a) 4.2 grams of propene, 1.8 grams of water.
(b) 6.0 grams of propene, 0.0 grams of water.
(c) 0.0 grams of propene, 6.0 grams of water.
(d) 1.8 grams of propene, 4.2 grams of water.
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25. The difference between an endothermic and exothermic reaction is that an endothermic reaction
(a) requires a continual supply of energy but an exothermic reaction does not.
(b) absorbs energy but an exothermic reaction releases energy.
(c) occurs best at low temperatures while an exothermic reaction occurs best at high temperatures.
(d) has energy as a product and an exothermic reaction has energy as a reactant.
26. The yeast in bread dough feeds on sugar to produce carbon dioxide. Why does the dough rise faster in a
warmer area?
(a) The yeast tends to "wake up" with warmer temperatures, which is why baker's yeast is best stored in the
refrigerator.
(b) There are a greater number of effective collisions among reacting molecules.
(c) Atmospheric pressure decreases with increasing temperature.
(d) The rate of evaporation increases with increasing temperature.
26. Carefully examine the following reaction sequence for the catalytic formation of ozone, O3, from molecular
oxygen, O2. Which chemical compound is behaving as the catalyst?
O2
+
2 NO
2 NO2
2 NO2
2O
+
2 NO +
2 O2
2O
2 O3
(a) nitrogen dioxide, NO2
(b) oxygen, O2
(c) nitrogen monoxide, NO
(d) atomic oxygen, O
27. The two components that make up a buffer include a
(a) strong acid and a weak acid.
(b) weak acid and the salt of this weak acid.
(c) strong acid and a strong base.
28. Sodium bicarbonate, NaHCO3 (shown below), is the active ingredient in baking soda. A solution of this
compound moderates changes in pH because
H O
O
C
O Na
sodium bicarbonate
(a) Sodium bicarbonate is like a buffer, the hydrogen end of the molecule is similar to a weak base.
(b) Sodium bicarbonate is like two buffer components combined into one molecule, the hydrogen end of the
molecule is similar to a weak base, and the sodium end is like a weak acid.
(c) Sodium bicarbonate is like a buffer, the sodium end of the molecule is like a weak acid.
(d) Sodium bicarbonate is like two buffer components combined into one molecule, the hydrogen end of the
molecule is similar to a weak acid, and the sodium end is like a weak base.
5
29. What salt is formed when a solution of sodium hydroxide, NaOH, is neutralized by sulfuric acid, H2SO4?
(a) H-OH
(b) NaSO4
(c) Na2SO4
(d) NaH
SHORT ANSWER: (SHOW ALL OF YOUR WORK!)
41. [8 MARKS] How much energy is released or absorbed when 2 moles of nitrogen, N2, reacts with 6 moles of
hydrogen, H2, to produce 4 moles of ammonia, NH3?
N N +
H-H
NH3
(Bond energies: N N 946 kJ/mole; H-H 436 kJ/mole; N-H 389 kJ/mole)
Is this reaction endothermic or exothermic?________________
6
43. [10
MARKS]
How many molecules of aspirin, C9H8O4, are there in a 0.250 gram sample? How many atoms?
44. [4 MARKS] Identify each of the substances in the following reactions as acting as an acid or base
(a)
PH3
(b)
HSO4–
+
(c)
HSO4–
+
(d)
PH3
+
+
+
H3S+
H2O
OH–
+
H2SO4
H2O
H3O+
+
SO42–
+
SH–
PH2–
H2S
H2S
PH4+
7
PHYSICAL SCIENCE FORMULA SHEET
Shape
h
b
Name
Formula
Rectangle
bh
Shape
h
w
l
Square
s2
Parallelogram
bh
Triangle
½bh
s
h
b
h
s
r
l
Name
Formula
Box
lwh
Cube
s3
r2l
Cylinder
4 3
r
3
Sphere
b
Circle
r
Quadratic Formula
r2
Half-life
to solve an equation of the form
ax 2 + bx + c = 0
1
Amount Remaining = Initial Amount ×
2
total time elapsed
half-life
use
x=
b ± b2 4ac
2a
Avogadros’ Number 6.02 x 1023
[H3O+] [OH–] = 1.0 x 10-14
pH= – log [H3O+]
8
PERIODIC TABLE OF THE ELEMENTS
1
1.0079
2
4.003
H
hydrogen
hydrogène
3
6.941
Li
lithium
lithium
11
22.99
Na
sodium
sodium
19
39.098
K
potassium
potassium
37
85.468
Rb
rubidium
rubidium
55
132.91
Cs
cesium
césium
87
223
Fr
francium
francium
He
atomic number
atomic mass
4
9.012
Be
5
10.811
Symbol
beryllium
béryllium
12
24.31
B
English name
French name*
boron
bore
13
26.98
*all are masculine
Mg
magnesium
magnésium
20
40.08
Ca
calcium
calcium
38
87.62
Sr
strontium
strontium
56
137.33
Ba
barium
baryum
88
226.03
Ra
radium
radium
6
12.011
21
44.96
Sc
scandium
scandium
39
88.91
Y
yttrium
yttrium
57
138.91
La
lanthanum
lanthane
89
227.03
Ac
actinium
actinium
22
47.87
Ti
titanium
titane
40
91.22
Zr
zirconium
zirconium
72
178.49
Hf
hafnium
hafnium
104
261
Rf
23
50.94
V
vanadium
vanadium
41
92.91
Nb
niobium
niobium
73
180.95
Ta
tantalum
tantale
105
262
Cr
chromium
chrome
42
95.94
25
54.94
Mn
manganese
manganèse
43
98
Mo
molybdenum
molybdène
74
183.84
W
tungsten
tungstène
106
266
Tc
technetium
technétium
75
186.21
Re
rhenium
rhénium
107
264
Ru
ruthenium
ruthénium
76
190.21
Co
cobalt
cobalt
45
102.91
Rh
rhodium
rhodium
77
192.22
Os
osmium
osmium
108
269
Ni
nickel
nickel
46
106.42
Pd
palladium
palladium
78
195.08
Ir
iridium
iridium
109
268
Cu
copper
cuivre
47
107.87
Ag
silver
argent
79
196.97
Au
gold
or
111
272
30
65.39
Zn
zinc
zinc
48
112.411
Uuu
unununium
unununium
ununbium
ununbium
58
140.12
61
145
62
150.36
63
151.96
64
157.25
65
158.93
66
162.50
90
232.038
Th
thorium
thorium
Pa
protactinium
protactinium
Nd
C
N
O
nitrogen
azote
15
30.974
oxygen
oxygène
16
32.07
Ge
germanium
germanium
50
118.71
Sn
tin
étain
82
207.2
P
phosphorus
phosphore
33
74.922
As
arsenic
arsenic
51
121.76
S
sulfur
soufre
34
78.96
Pb
Bi
Cl
chlorine
chlore
35
79.904
Se
selenium
sélénium
52
127.60
Sb
antimony
antimoine
83
208.98
F
fluorine
fluor
17
35.453
Br
bromine
brome
53
126.904
Te
tellurium
tellure
84
209
I
iodine
iode
85
210
Po
At
thallium
thallium
lead
plomb
bismuth
bismuth
polonium
polonium
astatine
astate
67
164.93
68
167.26
69
168.93
70
173.04
71
174.97
Sm
Eu
samarium
samarium
europium
europium
gadolinium
gadolinium
terbium
terbium
dysprosium
dysprosium
holmium
holmium
erbium
erbium
thulium
thulium
ytterbium
ytterbium
lutetium
lutécium
92
238.029
93
237.048
94
244
95
243
96
247
97
247
98
251
99
252
100
257
101
258
102
259
103
262
Np
neptunium
neptunium
Pu
Am
plutonium
plutonium
americium
américium
Cm
curium
curium
Tb
Bk
berkelium
berkélium
Ne
neon
néon
18
39.95
Ar
argon
argon
36
83.80
Kr
krypton
krypton
54
131.29
Xe
xenon
xénon
86
222
Rn
radon
radon
Uub
promethium
prométhium
U
Gd
Tl
Si
silicon
silicium
32
72.61
9
18.998
neodymium
néodyme
uranium
uranium
Pm
In
indium
indium
81
204.38
Hg
mercury
mercure
112
277
Uun
Pr
Ga
gallium
gallium
49
114.82
Cd
cadmium
cadmium
80
200.59
ununnilium
ununnilium
praseodymium
praséodyme
91
231.036
Une
Pt
platinum
platine
110
269
29
63.546
unnilennium
unnilennium
Ce
Uno
28
58.69
unnilloctium
unnilennium
60
144.24
Uns
Fe
iron
fer
44
101.07
27
58.93
unnilseptium
unnilseptium
59
140.91
Unh
26
55.85
rutherfordium unnilpentium unnilhexium
rutherfordium unnilpentium unnilhexium
cerium
cérium
Unp
24
51.996
8
15.9994
carbon
carbone
14
28.086
Al
aluminum
aluminium
31
69.72
7
14.007
helium
hélium
10
20.18
Dy
Cf
californium
californium
Ho
Es
einsteinium
einsteinium
Er
Fm
fermium
fermium
Tm
Md
Yb
No
mendelevium nobelium
mendélévium nobélium
Lu
Lr
lawrencium
lawrencium
9