Chemistry 12 Spring 2006
Examination #1 ANSWER KEY
Directions:
Select the best answer choice for the questions below, and mark the
answers on your scantron. Then answer the free response questions that follow (100 pts.
total; multiple choice 2 pts. each).
1.
Which of the following group of elements is considered the least reactive?
A.
B.
C.
D.
E.
2.
The total number of protons, neutrons, and electrons in
A.
B.
C.
D.
E.
3.
135
Ba2+ are:
135 protons; 79 neutrons; 137 electrons
135 protons; 79 neutrons; 133 electrons
56 protons; 79 neutrons; 58 electrons
56 protons; 79 neutrons; 54 electrons
56 protons; 135 neutrons; 133 electrons
From ammonia gas, one can obtain two different gases, each of which is a pure
substance. Using only this information, it can be said with certainty that:
A.
B.
C.
D.
E.
4.
alkali metals
alkaline earth metals
halogens
noble gases
transition metals
one of the products is an element.
neither of the products can be an element.
ammonia cannot be an element.
both products are elements.
gases do not produce solids.
Which of the following statements is true concerning the masses of individual Cl
atoms?
A.
B.
C.
D.
E.
All atoms have a mass of 35.45 amu.
None of the atoms have a mass of 35.45 amu.
Some of the atoms have a mass of 35.45 amu.
Most of the atoms have a mass of 35.45 amu.
All atoms have a mass of 17 amu.
5.
Which of the following statements about atoms and subatomic particles is
correct?
A.
B.
C.
D.
E.
6.
Rubidium possesses two stable forms. 85 Rb has a mass of 84.9 amu and a percent
abundance of 72.2%. What is the mass of the other form of Rb?
A.
B.
C.
D.
E.
7.
precise; not accurate
precise; accurate
not precise; not accurate
not precise; accurate
Insufficient data
4 mg = ? dag
A.
B.
C.
D.
E.
9.
86.9 amu ? Spring 2006 students note change here; all students were
given credit for this problem!
85.7 amu
88.3 amu
86.1 amu
89.4 amu
A student measuring the volume of a solid sample (actual volume = 12.49 cm3 )
reported the following results: 12.37 cm3 , 12.41 cm3 , 12.39 cm3 , and 12.38 cm3 .
Which of the following represents the best analysis of the student’s data?
A.
B.
C.
D.
E.
8.
Rutherford discovered the atomic nucleus by bombarding gold foil with
electrons.
Isotopes differ in the number of electrons present around the nucleus.
The neutron’s mass is equal to that of a proton plus an electron.
A neutral atom contains equal numbers of protons and electrons.
An atomic nucleus contains equal numbers of protons and neutrons.
4 x 10-3
4 x 103
4 x 104
4 x 10-2
4 x 10-4
A 16.0 g sample of iron has a volume of 2.035 cm3 . What is its density in g/mL?
A.
B.
C.
D.
E.
0.127 g/mL
32.6 g/mL
7.86 g/mL
7.862 g/mL
7.9 g/mL
10.
Perform the following calculation and express the result with the appropriate
number of significant figures: (1.302 + 953.2)/2.0 = ?
A.
B.
C.
D.
E.
11.
Which of the following is NOT a property of most metals?
A.
B.
C.
D.
E.
12.
234 g
739 g
468 g
593 g
369 g
Aluminum reacts with a certain element to form a compound with the general
formula Al2 X3 . What would the most likely formula be for the compound formed
between sodium and element X?
A.
B.
C.
D.
E.
14.
malleable
ductile
good conductors of heat and electricity
readily gain electrons when ionized
All of the above are true of most metals.
What is the mass of a 468 mL sample of ethanol? The density of ethanol is 0.789
g/mL.
A.
B.
C.
D.
E.
13.
4.80 x 102
477
4.8 x 102
477.3
477.25
Na2 X
NaX2
Na2 X3
Na2 X2
NaX
The speed needed to escape the pull of Earth’s gravity is 11.3 km/s. What is this
speed in mi/hr? (NOTE: 1 mi = 1.61 km)
A.
B.
C.
D.
E.
6.55 x 104 mi/hr
2.53 x 104 mi/hr
1.82 x 104 mi/hr
1.09 x 103 mi/hr
5.05 x 10-3 mi/hr
15.
The correct name for HClO 4 (aq) is:
A.
B.
C.
D.
E.
16.
All atoms of a given element have the same:
A.
B.
C.
D.
E.
17.
5.20 J
16.2 J
300. J
32.4 J
10.4 J
Which of the following physical processes involves changing a gas into a liquid?
A.
B.
C.
D.
E.
19.
mass number
atomic mass
atomic number
density
number of neutrons
The specific heat of liquid bromine is 0.226 J/g K. How much heat (in J) is
required to raise the temperature of 5.00 mL of bromine from 25.0 ºC to 29.6 ºC?
The density of liquid bromine is 3.12 g/mL.
A.
B.
C.
D.
E.
18.
perchloric acid
chloric acid
hyperchlorous acid
hyperchloric acid
chlorous acid
sublimation
deposition
condens ation
evaporation
freezing
Given that 1 inch = 2.54 cm, 1.00 cm3 is equal to:
A.
B.
C.
D.
E.
16.4 in3
6.45 in3
0.394 in3
0.155 in3
0.0610 in3
20.
Convert 15.8 ºF to degrees Celsius and Kelvin.
A.
B.
C.
D.
E.
21.
Write the symbol for the most common ion formed by phosphorus:
A.
B.
C.
D.
E.
22.
Dalton
Mendeleev
Moseley
Rutherford
Thomson
Which of the following is NOT part of Dalton’s original theory of atoms?
A.
B.
C.
D.
E.
24.
P-1
P-2
P-3
P+1
P+2
Which of the following scientists postulated that negatively charged electrons
were held within a positively charged sphere?
A.
B.
C.
D.
E.
23.
-40.6 ºC; 232.6 K
-57.6 ºC; 215.6 K
-73.0 ºC; 200.2 K
-9.0 ºC; 264.2 K
-117.0 ºC; 156.2 K
Atoms of different elements are different.
Compounds are formed by the joining of atoms of two or more elements.
All atoms of the same element are exactly alike; they all have the same
mass.
Elements are composed of atoms which are divisible and
indestructible particles.
All of the above statements ARE part of Dalton’s original theory of atoms.
Of the choices below, which one(s) is/are NOT an ionic compound?
A.
B.
C.
D.
E.
PCl3
K2 C2O4
MgBr2
Al2 O3
Both A and B
25.
What is the atomic symbol for radon?
A.
B.
C.
D.
E.
26.
R
Ra
Rd
Rn
D
(5 pts.) Calculate the length (in cm) of a steel cable, density = 7.91 g/cm3 , with a
mass of 160.0 g and a cross-sectional area of 0.500 cm2 .
density = mass/volume
volume = mass/density = 160.0 g/7.91 g/cm3 = 20.2 cm3
volume = length x width x height (any 2 multiplied components are “area”)
length = volume/area = 20.2 cm3 /0.500 cm2 = 40.4 cm
27.
(5 pts.) A plastic material weighing 3.81 oz is shaped into a cylinder 63.4 mm in
height and 1.64 inches in diameter. Determine the density in g/mL. Will this
object sink or float in water? Briefly explain. (NOTE: 1 oz = 28.35 g; 1 in =
2.54 cm)
mass = 3.81 oz x 28.35 g = 108 g
1 oz
diameter = 1.64 in x 2.54 cm = 4.17 cm
1 in
volume = pr2 h = p(4.17 cm/2)2 (6.34 cm) = 86.6 cm3
density = mass/volume = 1.25 g/mL (object will SINK in water since
density is greater than one)
28.
(30 pts. total; 2 pts. each) Write the name/chemical formula for each of the
following listed below:
A.
iron(III) hydroxide
Fe(OH)3
B.
Ca(H2 PO3 )2 · 3H2 O
C.
SnS2
tin(IV) sulfide
D.
ammonium oxalate
(NH4 )2 C2 O4
calcium dihydrogen phosphite trihydrate
29.
E.
carbonic acid
H2 CO3 (aq)
F.
IF5
iodine pentafluoride
G.
Zn(C 2 H3 O2 )2
zinc acetate
H.
HNO2 (aq)
nitrous acid
I.
Mn(SCN)2
manganese(II) thiocyanate
J.
tetraphosphorus decoxide
P4 O10
K.
silver chromate
Ag2 CrO4
L.
Li4 C
lithium carbide
M.
N2O5
dinitrogen pentoxide
N.
cadmium cyanide
Cd(CN)2
O.
HI
hydrogen iodide
(5 pts.) A 14.6 g sample of ethylene glycol loses 492 J of heat. What was the
initial temperature of the ethylene glycol if the final temperature is 25.8 ºC
(specific heat of ethylene glycol is 2.42 J/g K)?
q = mC?T
-492 J = (14.6 g)(2.42 J/g ºC)(25.8 – Ti )
Solve for Ti to obtain an initial temperature of 39.7 ºC.
30.
(5 pts.) Convert 13.7 dg/L to 1b/in3 . Express your final answer in scientific
notation. (Note: 1 lb = 454 g; 1 in = 2.54 cm)
lb = 1.37 g x 1 lb x 1 L x 1 mL x 2.54 cm x 2.54 cm x 2.54 cm
in3
L
454 g 1000 mL 1 cm3
1 in
1 in
1 in
= 4.94 x 10-5 lb/in3