Download Chemistry 1 Study Guide: 1st Quarter Exam

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Chemistry 1 Study Guide: 1st Quarter Exam
1. List the differenced between:
o Chemical change vs. Physical change and Exothermic vs. Endothermic
2.
Chemical
• Gas evolves
• Color change
• The substance becomes
another substance different
in chemical structure
• Can release or absorb lots
of energy
Physical
• Phase change such as
melting, cooling, dissolving
• Substance remains the same
substance
• Physical properties are:
Conducting electricity,
magnetism, density, etc.
Exothermic: Releases energy
Endothermic: Absorbs energy
What are the different types of matter?
o Pure Substances vs. Mixtures and Homogeneous vs. heterogeneous
Physical change
chemical change
3. Qualitative vs. Quantitative and Observation vs. Inference
Qualitative: Without numbers (Color,
smell, using other senses)
Quantitative: With numbers (mass,
temperature, density)
Observation: Using your senses to
describe an object or event
Inference: Using observations to make a
conclusion about an object or event
4. Density: How do you find it and how do you graph the data?
Density= mass divided by volume
o What needs to be on the graph?
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Graph mass on the y axis and volume on the x asis
Include units
Include a proper title
Include data points
o How do you draw a line of best fit and determine the slope?
• A line of best fit is drawn to show the trend of your data
• It“estimates” and does not need to go through each data point
• Do not use actual data points to calculate the slope
• Use points on the line beyond the data to calculate the slope.
o Indicate these points differently than the data
• Slope =∆y/∆x
5. Phases and molecular structure: Solid, Liquid, Gas
A=solid (pure substance)
B=liquid (mixture)
C=gas (mixture)
6. Balance a chemical Equation. What Law does this satisfy?
• 2KI + Pb(NO3)2 Æ PbI2 + 2KNO3
2 1-K-1 2
2 1-I-2
1-Pb-1
2-NO3-1 2
• The Law of Conservation of Matter. Matter cannot be created or
destroyed.
7. Melting/Freezing Point Graph and interpret the data. What is Temperature?
AÆB The warming of a solid. Molecules are vibrating faster as the solid warms
BÆC The melting point when energy is being used to break the physical bonds
CÆD The warming of a liquid. Matter is vibrating faster until it reaches the
boiling point.
Temperature is the measurement of matter’s movement. That is, temperature is
the measurement of the average kinetic energy of a substance.
8. Atomic Theory Scientists: How did their experiments explain the structure of an
atom during their time? Dalton, Thomson, Rutherford, Bohr, and others…
Greek
Earth, Wind, Fire, Water
Philosophers:
Democritus:
Dalton:
Thomson:
Rutherford:
“Atomos” Indivisible Particle
Atomic Theory Table 4.2
Bohr
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Electrons exist on energy levels
Energy levels get closer together
the further they get from the
nucleus
Bohrs model only can be used
for the 1st 20 elements
9. Define Atomic Number, Atomic Mass, Mass Number, Isotope
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Atomic Number: The number of protons
Atomic Mass: The average weighted mass of an element that is calculated
from the mass of each isotope and its percent abundance
Mass Number: protons + neutrons…The mass of an isotope
Isotope: An atom of an element that differs in mass from the number of
neutrons. Physically different but chemically the same.
10. Wave Properties: Define Amplitude, Frequency, Wavelength, and Energy.
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Amplitude: Height or depth from the center line of a wave
Frequency is cycles per second (ν)
Wave length: The complete cycle of a wave measured in seconds (λ)
The Energy of a wave can allow an electromagnetic wave to excite electrons.
Energy is proportional to frequency
o What is energy proportion to?
• Frequency
o How fast do electromagnetic waves move?
• The speed of light
• c= 300,000,000 m/s
o What has more energy? Blue or yellow light? Microwaves or x rays?
• Blue light
• X rays
11. Draw a Lewis Dot Diagram and a Bohr Diagram for the following: Na, Cl, C, Ne,
Al, Sr (Which one cannot be drawn with a Bohr Model? Why?) Write the
electron configuration for each. (long form)
•
Bohr Models can be done in class. Check your notes or the Lewis/Bohr
Worksheet.
•
You cannot build a Bohr Model past Calcium because the Bohr model is only for
energy levels. Beyond calcium the sublevels of the energy levels cross one
another. For example: 3d has more energy than 4s. The model would be to
confusing.
•
Therefore Sr cannot be drawn using a Bohr Model.
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Na: 1s22s22p63s1
Cl: 1s22s22p63s23p5
C: 1s22s22p2
Ne: 1s22s22p6
Al : 1s22s22p63s23p1
Sr: 1s22s22p63s23p64s23d104p65s2
12. What is a metal? Non-Metal? Metalloid? List the properties
o Give an example of each?
o Which is likely to have a positive charge? Negative Charge?
Metal
• Good conductor of
electricity and heat
• On the left of the PT
• Typically solid at room
temp
• Shiny, luster, malleable
• Lose electrons to form
positively charged atoms
• Usually between 1 and 4
valence electrons
• Fe, Au, Li, Zn
Nonmetal
• Poor conductor of
electricity and
heat
• On the Right of
the PT
• All phases at
room temp
• Brittle if solid
• Gain electrons to
form negatively
charged atoms
• Usually between
4 and 8 valence
electrons
• C, P, He, I
Metalloid
• Has both properties
of metals and
nonmetals
• Typically shares
electrons
• Between 4 and 7
valence electrons
• Si, B, As
13. What is an orbital? How many electrons fit in one orbital? How many electrons
fit in all the orbitals of the following sublevels: s, p, d, f?
• Orbital- an electron cloud that can hold up to 2 electrons
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S
P
D
F
2 e6 e10 e14 e-
o Which electron has more energy?
4f
14. Name the family, group number, and period number of the following atoms: Na,
Cl, Zn, Ar, Ca
Na
Cl
Zn
Ar
Ca
Family
Alkali Metal
Halogen
Transition Metal
Nobel Gas
Alkaline Earth Metal
Group
1
17
12
18
2
Period
3
3
4
3
4
o Which is most likely to take away an electron?
• Cl
o Which is most likely to lose an electron?
similar
K
F
Hg
Ne
Mg
• Na
o Give an example of another atom that is chemically similar to each listed
element.
• See the chart above under “similar”
o Which has the largest atomic radius?
• Na
o Which has the largest ionization energy?
• Cl
Fill in the chart.
In nucleus
(Yes / No)
Charge
(-1, 0, +1)
Relative Mass
(1 amu, 0 amu)
4. Proton
Yes
+1
1 amu
5. Electron
No
-1
0 amu
6. Neutron
Yes
0
1 amu
15. Calculate the atomic mass of Magnesium given the following information:
Isotope
% Abundance
Mg 24
79.0%
Mg-25
10.1%
Mg-26
10.9%
(24amu x 0.790) + (25 amu x 0.101) + (26 amu x 0.109)
Atomic Mass = 24.3 amu
16. Draw a diagram of a Chlorine-37 atom. Label all parts of the atom and indicate
where each subatomic particle is located.
See instructor or the Atomic Theory Quiz
17. Fill in the chart.
Element/Charge Atomic
Mass
# of
# of
# of
Number
Number
Protons
Neutrons
Electrons
Na
11
23
11
12
11
P
15
31
15
16
15
Al
13
28
13
15
13
S
16
34
16
18
16
*Remember: Charge on an element denotes a loss or gain of electrons.
Now write an electron configuration for all of the above Elements or Ions. (Do not
write it as an abbreviated noble gas form)
Na: 1s22s22p63s1
P:1s22s22p63s23p3
Al3+:1s22s22p63s3
S:1s22s22p63s23p4