Midterm
Review
Worksheet
Solutions
1.
List and describe the steps of the scientific
method.
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2.
Problem – determine what you need an answer for
Observations – observe the situation
Scientific Hypothesis – make an educated guess
based on your observations
Test – perform an experiment
Conclusion – determine if your hypothesis is correct
Determine the number of significant figures in
each of the following measurements:
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2050 mL = 3 sig figs
0.010230 mm = 5 sig figs
0.0023032 g = 5 sig figs
200.400 mL = 6 sig figs
3.
Calculate the following to the correct number of
significant figures:
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4.
12.0302 + 45.1 + 6.24 = 63.3702 = 63.4
625.23 – 52.32154 = 572.90846 = 572.91
4.82 * 6.1 = 29.402 = 29
625.214 / 12.2 = 51.24704918 = 51.2
Put the following numbers into scientific notation:
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0.000032871 = 3.2871 x 10-5
998.227 = 9.98227 x 102
5.
Use factor label to perform the following
conversions (SHOW ALL WORK):
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125 cm = ? m
1𝑚
125 𝑐𝑚
= 1.25 𝑚
100 𝑐𝑚
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725 lb = ? ton
0.45 𝑘𝑔
725 𝑙𝑏
1 𝑙𝑏
0.001 𝑡𝑜𝑛
= 0.326 𝑡𝑜𝑛
1 𝑘𝑔
54000 µm = ? cm
1𝑚
54000µ𝑚
1,000,000 µ𝑚
25 mi/h = ? m/s
25 𝑚𝑖 5280 𝑓𝑡
1𝑚
ℎ
1 𝑚𝑖
3.281 𝑓𝑡
100 𝑐𝑚
= 5.4 𝑐𝑚
1𝑚
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1ℎ
60 𝑚𝑖𝑛
1 𝑚𝑖𝑛
= 11 𝑚/𝑠
60 𝑠
6.
What is the density of a diamond that has a
volume of 0.35 mL and a mass of 1.14 g?
𝑀
1.14 𝑔
𝑔
𝐷= =
= 3.3
(𝑖𝑛 𝑠𝑖𝑔 𝑓𝑖𝑔𝑠)
𝑉 0.35 𝑚𝐿
𝑚𝐿
7.
If the accepted density for the sample in
problem #6 is 3.28 g/mL, calculate the percent
error for your calculation.
𝑎−𝑜
3.28 − 3.3
% 𝑒𝑟𝑟𝑜𝑟 =
∗ 100% =
∗ 100% = 0.61%
𝑎
3.28
Identify the type of energy contained in:
8.
A.
B.
C.
A baseball that has just been thrown: Kinetic
A book hanging on the end of a shelf: Potential
Light from a light bulb: Radiant
List the distinguishing characteristics of solids, liquids,
and gases:
9.
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10.
a.
b.
c.
d.
e.
f.
Solids: Definite volume, definite shape
Liquids: Definite volume, indefinite shape
Gases: Indefinite volume, indefinite shape
Identify the following as a physical or chemical
change:
Tearing a piece of paper – Physical
A plant converting sunlight to food – Chemical
Burning wood in a fireplace – Chemical
Melting snow – Physical
Baking a cake – Chemical
Crushing rock - Physical
11.
Identify each as an element, compound,
homogeneous mixture, or heterogeneous
mixture:
a)
b)
c)
d)
e)
f)
g)
h)
i)
Alphabet soup – heterogeneous mixture
Salt – compound
Vegetable Oil – compound
Air – homogeneous mixture
Steel – homogeneous mixture
Sugar – compound
Pure water – compound
Tap water – homogeneous mixture
Sea water – heterogeneous mixture
12.
What is the law of conservation of mass?
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13.
Describe the contributions of Aristotle and
Democritus
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14.
Mass can neither be created nor destroyed in any
chemical reaction
Aristotle believed that there were four elements:
Earth, Air, Fire, and Water
Democritus believed that all matter was made up of
tiny, indivisible particles
Explain Dalton’s Atomic Theory and his model
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Postulates that explained what he believed about
atoms
Billiard ball model of the atom – solid sphere of
uniform density
15.
Describe Thomson’s model of the atom. What was
it called?
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16.
Describe the experiment done by Rutherford.
What was it called? What did it explain? Describe
his model.
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17.
Thomson believed that there were negatively charged
subatomic particles called electrons floating in a
positive environment. His model is the plum pudding
model.
Gold Foil Experiment – proved that there was a large
concentration of positive charge in the center of the
atom – Rutherford called it the nucleus (Nuclear
model)
Define atomic number and mass number.
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Atomic number – the number of protons in an atom
Mass number – sum of protons and neutrons in an
atom
18.
Define ion. Describe how atoms become positive
or negative ions. What are each called?
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19.
Ion – atom that has lost or gained electrons and has
an overall charge
Positive ions lose electrons – Cations
Negative ions gain electrons - Anions
Determine the atomic number, mass number,
number of protons, neutrons, and electrons in
each of the following:
Atomic #
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Mass # P+
N0
E-
Calcium-44 20
44
20
24
20
13
27
13
14
13
8
18
8
10
8
34
78
34
44
34
17
35
17
18
18
27
𝐴𝑙
Oxygen-18
78
34𝑆𝑒
35 -1
17𝐶𝑙
20.
Find the average atomic mass of magnesium:
𝐴𝐴𝑀 = 23.985 ∙ 0.7899 + 24.986 ∙ 0.100 + 25.983 ∙ 0.1101
= 24.31 amu
21.
Write the nuclear equation for the alpha decay of
gold-185
185
79𝐴𝑢
22.
→ 42𝛼 + 181
77𝐼𝑟
Write the nuclear equation for the beta decay of
uranium-238
238
92𝑈
→
0
−1𝛽
+ 238
93𝑁𝑝
23.
A photon of visible light has a wavelength
of 528 nm. Find the frequency of the light
and the energy it contains.
1𝑚
528 𝑛𝑚
= 5.28𝑥10−7 𝑚
1,000,000,000 𝑛𝑚
𝑐 3.0𝑥108 𝑚/𝑠
14 𝐻𝑧
ν= =
=
5.68𝑥10
λ 5.28𝑥10−7 𝑚
𝐸 = ℎν = 6.626𝑥10−34 𝐽 ∙ 𝑠 5.68𝑥1014 𝐻𝑧
= 3.76𝑥10−19 𝐽
24.
A certain wave has 3.78x10-19 J of energy. Find the
wavelength and frequency.
𝐸 = ℎ𝜈 ⇒ 3.78𝑥10−19 = (6.626𝑥10−34 )ν ⇒ 5.70𝑥1014 𝐻𝑧
25.
𝑐
3.0𝑥108 𝑚/𝑠
−7 𝑚
𝜆= =
=
5.26𝑥10
ν 5.70𝑥1014 𝐻𝑧
Explain: Aufbau principle, Pauli Exclusion principle,
and Hund’s Rule
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Aufbau principle – Orbitals fill from the lowest energy to the
highest
Pauli Exclusion principle- Any two electrons that occupy
the same orbital must have opposing spins
Hund’s Rule – electrons fill all empty orbitals within a
sublevel
26.
Draw the orbital diagram of Cadmium and write the
full electron configuration. How many unpaired
electrons are there?
1s 2s 2p    3s 3p   
4s 3d     4p    5s 4d    
1s22s22p63s23p64s23d104p65s24d10 - Zero unpaired e27.
Write the abbreviated (noble gas) configuration for
Iodine.
[Kr] 5s24d105p5
26.
Write the full electron configuration for Se-2.
1s22s22p63s23p64s23d104p65s2
29.
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Give the contributions to the periodic table from
each of the following scientists:
Mendeleev: First Periodic Table
Moseley: Discovery of atomic number/protons
determining the identity of the element
Dobereiner – Organized the elements into Triads
Newlands – Organized the elements into Octaves
30.
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Tell the name of the group that each of the
following elements belongs to:
Calcium – alkaline earth metal
Argon – noble gas
Silicon – carbon group
Iodine – halogen
•
•
•
•
Cesium – alkali metal
Sulfur – oxygen group
Aluminum – boron group
Antimony – nitrogen group
31.
Identify each of the above elements as a metal,
non-metal, or metalloid:
Calcium – metal
Argon – non metal
Silicon – metalloid
Iodine – non metal
•
•
•
•
32.
What are the properties of metals?
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33.
•
•
•
•
34.
Cesium – metal
Sulfur – non metal
Aluminum – metal
Antimony – metalloid
•
•
•
•
Malleable, ductile, lustrous, conduct electricity
Circle which element is smaller:
Ca or Ga
Be or Mg
Br or I
Tl or Pb
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•
•
•
Na or Na+
O or O2Br or its ion (Br1-)
Sr or its ion (Sr2+)
Circle which has a higher ionization energy:
• K or Ca
• P or Sb
• Al or Si
• Rb or Fr
37.
Circle which element is more electronegative:
• N or F
• Al or Si
• Rb or Sn
• Ca or Ba
• As or Bi