Transcript Practice Question

Seminar:
Test 1 Review
Freddie Arocho-Perez
Kaplan University
SC155: Introduction to Chemistry
General Information
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Access Dates:
Wednesday, May 12 – Tuesday, May 25
During the time that the test is available, you may
take it anytime you wish and as many times as you
want. Only the last submission will be saved and
graded.
I made it available for more time than I originally
noted in the syllabus. The only reason I did this was
because I assume most of you may want to work on
this test on evenings and weekends.
General Information
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The questions have been formulated by me
(Instructor) and the Science Instructional
Committee. I did apply this change in order to
make the test content more related to our
seminars and discussions.
The test consists of 30-multiple choice
questions.
Study Guide sent by e-mail and posted in
DocSharing.
General Information
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The test questions will account for reading
comprehension, applications, definitions, and
mathematical analysis.
There will be 9 math-related questions, coming
specially from the material included in:
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“Seminar: Math Review Session”
“Seminar: Elements, Compounds, and Chemical Reactions”
Useful Materials:
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Calculator
Periodic Table (see DocSharing for a hand-out)
Conversion Factors (see hand-outs “Metric and English
Conversion Factors” and “Math Review: Metric System /
Dimensional Analysis” in DocSharing)
Practice Question
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Which of the following element/chemical
symbol pairs is incorrectly matched?
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Chromium: Cr
Rubidium: Rb
Scandium: S
Argon: Ar
Gold: Au
Practice Question
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Which of the following element/chemical
symbol pairs is incorrectly matched?
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Chromium: Cr
Rubidium: Rb
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Scandium: S
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Argon: Ar
Gold: Au
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Solution: Practice Question
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From the Periodic Table:
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Scandium: Sc
Atomic Number: 21
Sulfur: S
Atomic Number: 16
Practice Question
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Which of the following statements is
incorrect?
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All atoms of an element have the same atomic
number.
All atoms of an element must have the same
mass.
All atoms of an element have the same number of
protons.
Atoms of an element may have different numbers
of neutrons.
Practice Question
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Which of the following statements is
incorrect?
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All atoms of an element have the same atomic
number.
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All atoms of an element must have the
same mass.
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All atoms of an element have the same number of
protons.
Atoms of an element may have different numbers
of neutrons.
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Solution: Practice Question
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All atoms of an element have the same atomic
number = TRUE
All atoms of an element must have the same mass =
FALSE
All atoms of an element have the same number of
protons = TRUE
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(# Protons = Atomic Number)
Atoms of an element may have different numbers of
neutrons = TRUE
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Isotopes: different forms of an element each having different
atomic mass. Isotopes of an element have the same
number of protons (the same atomic number) but different
numbers of neutrons.
Practice Question
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Which of the following involves
chemistry?
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automobiles
detergents
cooking
all of the above
Practice Question
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Which of the following involves
chemistry?
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automobiles
detergents
cooking
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all of the above
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Solution: Practice Question
 Chemistry
is EVERYWHERE!!!!
Practice Question
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Tap water consists of water, sodium and
chloride ions, and possibly bacteria, chlorine,
and other ingredients. Which choice best
defines what tap water is?
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a molecule
an element
a mixture
a compound
Practice Question
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Tap water consists of water, sodium and
chloride ions, and possibly bacteria, chlorine,
and other ingredients. Which choice best
defines what tap water is?
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a molecule
an element
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a mixture
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a compound
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Solution: Practice Question
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Pure Substance: A sample of matter, either an
element or a compound, that consists of only one
component with definite physical and chemical
properties and a definite composition.
Element: Substance consisting of only one type of
atom.
Compound: Two or more atoms joined together
chemically (with bonds).
Mixture: Composed of two or more substances, but
each keeps its original properties.
Practice Question
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Calculate how many liters of liquid are in a
container that has 579 mL of the liquid.
(1 L = 1,000 mL)
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5.79 L
0.0579 L
0.579 L
57.9 L
Practice Question
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Calculate how many liters of liquid are in a
container that has 579 mL of the liquid.
(1 L = 1,000 mL)
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5.79 L
0.0579 L
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0.579 L
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57.9 L
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Solution: Practice Question
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Conversion Factor:
1 L = 1,000 mL
Use Dimensional Analysis:
1L
579mL 
 0.579 L
1,000mL
Practice Question
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How many grams are contained in 3.20
pounds?
(1 pound = 453.6 g)
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678.2 g
964.3 g
1,322.2 g
1,451.5 g
Practice Question
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How many grams are contained in 3.20
pounds?
(1 pound = 453.6 g)
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678.2 g
964.3 g
1,322.2 g
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1,451.5 g
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Solution: Practice Question
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Conversion Factor:
1 pound = 453.6 g
Use Dimensional Analysis:
453.6 grams
3.20 pounds 
 1,451.5 grams
1 pound
Practice Question
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Which component of the atom has no
charge?
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electrons
protons
neutrons
all components have a charge
Practice Question
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Which component of the atom has no
charge?
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electrons
protons
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neutrons
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all components have a charge
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Solution: Practice Question
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Sub-atomic Particles:
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Center of the Atom:
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Protons: Positive (+) Charge
Electrons: Negative (-) Charge
Neutrons: Neutral (0) Charge
Protons
Neutrons
Surrounding the Center of the Atom:
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Electrons
Practice Question
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Which of the following is an example of a
chemical property of water? It
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boils at 100 C.
is transparent.
has no odor.
reacts with calcium.
Practice Question
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Which of the following is an example of a
chemical property of water? It
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boils at 100 C.
is transparent.
has no odor.
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reacts with calcium.
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Solution: Practice Question
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A chemical property of a substance is how the
substance reacts with other substances and
what new products may form.
A physical property describes the substance’s
characteristics.
An example of a chemical property is how
substances react to heat (flammability) or acid.
An example of a physical property is the
melting point or density of a substance.
Solution: Practice Question
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Water:
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Physical properties: it melts at 0 C, boils at 100 C
(at sea level), transparent, odorless, density is 1.0
g/cm3.
Chemical properties: reacts with some metals like
Calcium quickly, reacts with other metals slowly to
form rust. Doesn’t burn.
Salt:
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Physical: white, crystalline, high melting point.
Chemical: doesn’t burn, doesn’t react with acid.
Practice Question
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Which of the following is an example of a
physical property of hydrogen? It
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is less dense than air.
reacts with oxygen.
is highly flammable.
forms hydrochloric acid.
Practice Question
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Which of the following is an example of a
physical property of hydrogen? It
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is less dense than air.
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reacts with oxygen.
is highly flammable.
forms hydrochloric acid.
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Mass Relations
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Atomic Mass vs. Molecular Mass:
– Atomic Mass: Mass of the atom of an element.
– Molecular Mass: Mass of a molecule; Sum of the atomic
masses of the atoms in a molecule.
– amu: atomic mass units.
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From the Periodic Table, we can obtain atomic masses:
C = 12.01 amu
Ca = 40.08 amu
H = 1.008 amu
K = 39.10 amu
P = 30.97 amu
S = 32.07 amu
O = 16.00 amu
Mass Relations
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Atomic masses:
C = 12.01 amu
Ca = 40.08 amu
H = 1.008 amu
K = 39.10 amu
P = 30.97 amu
S = 32.07 amu
O = 16.00 amu
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Calculate the molecular mass of H2O:
H: 2 atoms X 1.008 = 2.016
O: 1 atom X 16.00 = 16.00
Total: 18.016 ~ 18.02 amu
Mass Relations
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Atomic masses:
C = 12.01 amu
Ca = 40.08 amu
H = 1.008 amu
K = 39.10 amu
P = 30.97 amu
S = 32.07 amu
O = 16.00 amu
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Calculate the molecular mass of CO2:
C: 1 atom X 12.01 = 12.01
O: 2 atoms X 16.00 = 32.00
Total: 44.01 amu
Practice Question
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Atomic masses:
C = 12.01 amu
Ca = 40.08 amu
H = 1.008 amu
K = 39.10 amu
P = 30.97 amu
S = 32.07 amu
O = 16.00 amu
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Calculate the molecular mass of CH4:
Practice Question
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Atomic masses:
C = 12.01 amu
Ca = 40.08 amu
H = 1.008 amu
K = 39.10 amu
P = 30.97 amu
S = 32.07 amu
O = 16.00 amu
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Calculate the molecular mass of CH4:
C: 1 atom X 12.01 = 12.01
H: 4 atoms X 1.008 = 4.032
Total: 16.042 ~ 16.04 amu
Practice Question
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48 C is approximately the same as
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341 K.
321 K.
285 K.
205 K.
158 K.
Practice Question
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48 C is approximately the same as
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341 K.
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321 K.
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285 K.
205 K.
158 K.
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Solution: Practice Question
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This is a temperature conversion problem:
K = C + 273.15
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K = 48 + 273.15
= 321.15
= 321
(rounded)
Practice Question
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120.0 C is approximately the same as
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100 F.
159 F.
207 F.
248 F.
306 F.
Practice Question
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120.0 C is approximately the same as
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100 F.
159 F.
207 F.
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248 F.
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306 F.
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Solution: Practice Question
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This is a temperature conversion problem
F = (1.8 x C) + 32
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F = (1.8 x 120.0) + 32
= 216 + 32
= 248
(rounded)
Practice Question
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Atomic masses:
C = 12.01 amu
Ca = 40.08 amu
H = 1.008 amu
K = 39.10 amu
P = 30.97 amu
S = 32.07 amu
O = 16.00 amu
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Calculate the molecular mass of K2SO4:
Practice Question
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Atomic masses:
C = 12.01 amu
Ca = 40.08 amu
H = 1.008 amu
K = 39.10 amu
P = 30.97 amu
S = 32.07 amu
O = 16.00 amu
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Calculate the molecular mass of K2SO4:
K: 2 atoms X 39.10 = 78.20
S: 1 atom X 32.07 = 32.07
O: 4 atoms X 16.00 = 64.00
Total: 174.27 amu