Benchmark
Mid-Term
Study Guide
Chapter 1: Introduction to Chemistry
A systematic approach that scientists use:
• Scientific method
1. Observation
2. hypothesis
3. experiment
4. results/Data
5. Conclusions
6. theory
7. law
Matching
B 6. refers to physical characteristics such as color, odor, or shape
___
C 7. refers to mass, volume, and temperature measurements
___
D 8. a variable controlled by the experimenter
___
___
A 9. the act of gathering information
E 10. changes in value based on the value of the controlled variable
___
a.
b.
c.
d.
e.
Observation
Qualitative data
Quantitative data
Independent variable
Dependent variable
Multiple Choice
11.
A constant is a factor that
a.
b.
c.
d.
Changes during an experiment
Changes from one lab group to another
Is affected by the dependent variable
Is not allowed to change during an
experiment
Matching
12. A control is
a. Variable that changes during an
experiment
b. Standard for comparison
c. Type of dependent variable
d. Type of experiment
Matching
13. A hypothesis is a(n)
a. Educated Guess
b. Explanation supported by many
experiments
c. Tentative explanation of
observations
d. Law describing a relationship in
time
Matching
14. A theory is a(n)
a. Set of controlled observations
b. Explanation supported by many
experiments
c. Tentative explanation of
observations
d. Law describing a relationship in
time
Matching
15. A law is a(n)
a. Set of controlled observations
b. Explanation supported by many
experiments
c. Tentative explanation of
observations
d. Law describing a relationship in
time
Matching
16. A model is a(n)
A visual, verbal, or mathematical.
GRAPH, Pie Chart
Completion
17. What piece of lab equipment should be used to
accurately measure volume? Graduated cylinder
18. What piece of lab equipment should be used to
Balance
accurately measure mass?
19. What is the proper technique for smelling a chemical in
the laboratory? Wafting
20. What is the proper technique for holding a test tube
Test tube holder
while heating?
Chapter 2: Data Analysis
1. Change the following data into scientific
notation.
a. 5,000,000 km 5 x 106 km
-4 g
4.21
x
10
b. 0.000421 g
-2 cm
3
x
10
c. 0.03 cm
2. Change the following data into ordinary
notation.
a. 5.3 x 1012
b. 4.0 x 105
c. 6.1 x 10-5
5,300,000,000,000
400,000
0.000061
3.Use the terms precise and accurate to describe the
following figures. You may use both terms for some
figures. If a term does not apply to a figure, leave the
space blank.
neither
Precise but
Not
accurate
Accurate &
precise
4. Students were asked to find the density of an unknown white
powder. Each student measured the volume and mass of three
separate samples. They reported calculated densities for each trial
and an average of the three calculations in the following data table.
The power was sucrose, also called table sugar, which has a density
of 1.59 g/cm3.
a. Which student’s measurements were most accurate?
A – because all of their values are close to the accepted value
of sugar, 1.59%
b. Which student’s measurement were most precise?
C – because all of their values are close together but not close
to the accepted value
Density Data Collected by Three Different Students
Student A
Student B
Student C
Trial 1
1.54 g/cm3
1.40 g/cm3
1.70 g/cm3
Trial 2
1.60 g/cm3
1.68 g/cm3
1.69 g/cm3
Trial 3
1.57 g/cm3
1.51 g/cm3
1.71 g/cm3
Average
1.57 g/cm3
1.51 g/cm3
1.70 g/cm3
5.
A sample of aluminum is placed in a 25 mL graduated
cylinder containing 10.0 mL of water. The level of water
rises to 18.0 mL. Aluminum has a density of 2.7 g/mL.
Calculate the mass of the sample. (Use appropriate
significant figures.)
18.0 mL
- 10.0 mL
8.0 mL
m = d(v)
= 2.7 g/mL(8.0mL)
= 21.6g = 22g
6. You have a 230g sample of ethanol with a
density of 0.7893 g/mL. What volume of
ethanol do you have? (use appropriate
significant figures)
v = m/d = 230g
0.7893g/mL = 291.4 = 290 mL
7. An object with a mass of 7.5g raises the
level of water in a graduated cylinder from
25.1 mL to 30.1 mL. What is the density of
the object?
30.1 mL
-25.1 mL
5.0 mL
d = m/v
7.5g
5.0mL
= 1.5 g/mL
8. Determine the volume indicated in Figure 1.
64.0 mL
9. Determine the length indicated by Letter H in Figure 2.
12.94 cm
10. Determine the volume indicated in Figure 3.
34.7 °C
Figure 3
Figure 1
Figure 2
Chapter 3 – Matter: Properties & Changes
mass
Matter is anything with (1) ____________________
and volume. A (2)
substance
____________________
is a form of matter with a uniform and
unchanging composition. Substances have specific, unchanging (3)
properties
____________________
that can be observed. Substances have both
physical
physical and chemical properties. (4) ____________________
properties can be observed without changing a substance’s chemical
density
composition. Color, hardness, and (5) ____________________
are
examples. Other properties cannot be observed without changing the
chemical
composition of a substance. These are called (6) __________________
properties. An example is the tendency of iron to form rust when exposed
to air.
chemical
mass
physical
density
properties
substance
• Label each property as either physical intensive, physical extensive,
or chemical.
Physicalintensive
Chemical
Physicalintensive
Physicalextensive
7.
Bitter taste
Physicalextensive
8.
length
9.
Corrosion
Physicalintensive
10.
Malleability
11.
Magnetic
12.
Flammability
13.
Volume
14.
Reacts with an
acid to form a gas
Chemical
Chemical
Intensive – doesn’t matter how much you have
Extensive – does matter how much you have
_____
True 15. A solid has definite shape and volume.
_____
False 16. A liquid has a definite shape and takes on the
volume of its container.
True 17. A gas has both the shape and the volume of its
_____
container.
False 18. The particles in a solid are spaced far apart.
_____
gas
19. ____________
solid
20. ____________
liquid
21. ____________
22.What are the four indicators that a chemical
change has taken place?
a. Temperature change
b. Color change
c. Gas (bubbles) produced
d. Precipitate (solid) formed
Identify the following as physical or chemical
changes
C
23.
Log burning
P
24. Making kool-aid
25.
Iron rusts in
air
C
26. Fermentation of
apple juice
27.
Milk sours
P
28. Slicing bread
29.
Water boiling
P
30. Dissolving NaCl
into H2O
C
C
P
Solution
Size of particles Too small to see
Composition
Tyndall effect
Settle Out
Clarity
Colloid
intermediate
homogeneous Heterogeneous
Suspension
visible/large
heterogeneous
Negative
positive
negative
No
No
Yes
Clear
Cloudy
Cloudy
Type of Matter
32. Water
Substance
compound
heterogeneous
33. Soil
homogeneous
34. Sugar water
35. Oxygen
36. Carbon dioxide
37. Rocky road
ice cream
Mixture
element
compound
heterogeneous
38. List four techniques that can be used to separate a
mixture.
a. Filtration
b. Distillation
c. Chromatography
d. crystallization
Chapter 4 – The Structure of the Atom
Subatomic particle
Location
Charge
Relative Mass
Proton
Inside
nucleus
+
1
Electron
Outside
nucleus
-
0
Neutron
Inside
nucleus
0
1
2. Most of an atom’s mass can be found in the
nucleus
______________.
3. The number of protons in an atom is its
atomic #
________________.
4. The number of protons + neutrons in an atom is its
mass #
______________.
protons always
5. In a neutral atom, the number of ______
electrons
equals the number
of __________.
6. Isotopes are atoms of an element with a different
mass #
________.
They have the same number of
protons but a different number of ____________.
neutrons
________
7. Use a periodic table to identify the following
elements.
a.
b.
c.
d.
47 protons Ag - silver
95 electrons Am - americium
Atomic number = 28 Ni - nickel
6 protons and 8 neutrons Carbon – 14
or
14
6
C
16
7
Isotope
Name
Oxygen–16
Symbolic
Notation
16
8
Nitrogen - 16
Bromine - 80
80
35
Number of Number of Number of
Protons
Electrons Neutrons
O
8
N
7
Br
35
8
7
35
8
9
45
9. Three isotopes of argon occur in nature
36
– 18
Ar,
38
40
Ar,
and
Ar. Calculate the average atomic mass
18
18
of argon to two decimal places, given the
following relative atomic masses and
abundances of each of the isotopes: argon–36
(35.97 amu; 0.337%), argon–38 (37.96 amu;
0.063%), and argon–40 (39.96 amu; 99.600%).
35.97 (0.00337) =
37.96 (0.00063) =
39.96 (0.996) =
0.1212
0.0239
39.800
39.945 amu
Chapter 25: Nuclear Chemistry
Radioactivity
Process where substances emit radiation
Radioisotopes
Unstable isotopes that are radioactive
Half-life
Time required for one-half of a radioisotope’s
nuclei to decay into its products
Nuclear fission
Splitting of a heavy nucleus into two smaller
nuclei (nuclear power plants)
Nuclear fusion
Combining two nuclei to form a heavier,
more stable nucleus – occurs in the sun
2. Nuclear reactions involve changes
in an atom’s nucleus, whereas
chemical reactions do not.
Type of
radiation
Alpha, α
Symbol
What is
it?
Can be
stopped
by
α
Particle
Paper
Beta, β
β
Particle
Wood/
aluminum
foil
Gamma, γ
Γ
wave
Lead/
concrete
Penetrating
Power
4
2
He
0
e
-1
energy