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hello im currently taking online chemistry classes on platoweb, i
have evrything done but the final exam and thses offline activities (the documents attached) im also taking other classes that i have to finish and i simply dont have the time to do them
© 2013 EDMENTUM, INC.
Unit 3: Chemical Bonding
This Unit Activity will help you meet these educational goals:
Science Inquiry— You will do online research, collect information, and analyze it. You
will communicate your results in tabular and written form.
STEM— You will use simulations and online research to understand scientific
reasoning. You will get an insight into STEM careers that are uniquely and personally
creative.
21
st
Century Skills— You will employ online tools for research and analysis.
Introduction
Since the 1970s, there’s been increasing public debate about greenhouse gases and global
warming. Is the Earth really on a warming trend or is it random variation? And even if the
Earth is warming, is it a natural process or is it caused by human activity? And if there is
warming caused by human activity, how critical is it, and what’s a reasonable way to deal with
it?
What’s not in dispute is that greenhouse gases exist and that they are observed to allow
visible light to pass through, but absorb and reemit infrared radiation. On a planetary scale,
this means that they allow the sun’s light energy to enter the atmosphere, then they retain
some of that energy in the atmosphere in the form of heat. That’s generally a good thing,
preventing wild temperature swings on Earth between night and day. A change in the Earth’s
greenhouse effect, however, would mean a change in the Earth’s climate over time. That
wouldn’t necessarily be a good thing.
In this unit activity, you will explore more about greenhouse gases on a molecular level. You
will use interactive molecular models of some key gases in the atmosphere to find out what
structural features differentiate greenhouse gases from other gases in air. You will also
research the various viewpoints regarding global warming and explain your views about
them.
__________________________________________________________________________
Directions and Analysis
Task 1: Greenhouse Effect and Global Warming
Read the basics about the
greenhouse effect
, then search the Internet for other authoritative
sources to answer the following scientific questions about this phenomenon.
Key search terms:
greenhouse effect, greenhouse gases, global warming
1
Chemistry
Unit Activity
1. Describe what the greenhouse effect is and how it is caused on a molecular level.
Type your response here:
2. How is the greenhouse effect related to global warming?
Type your response here:
3. List four greenhouse gases in the atmosphere. For each gas, describe its prevalence in
the atmosphere, its natural sources, its human-induced sources, and how its
concentration in the atmosphere might be changing.
Type your response here:
Task 2:
Molecular Models of Greenhouse Gases
Oxygen, carbon dioxide, and methane are present naturally in the atmosphere. While carbon
dioxide and methane are greenhouse gases, oxygen is not. Why not? To find the answer, go
to the
Cool Molecules Explore
site.
On the top menu, click
entry level
to reduce the total number of compounds. On the left
pane, click
bonds
. On the periodic table, select molecules by clicking the individual atoms
that form them (the molecules). For example, to select an oxygen (O
2
) molecule, perform the
following:
a. Click
O
, wait for a few seconds, and then click
O
again.
b. Scroll below to see the list of molecules the O-O bond form. Locate the O
2
(g)
molecule and click
view
.
c.
Below the molecular structure, a drop-down list contains the types of vibrations that
the molecule and its bonds undergo. In the “show vibration” box, select each
available vibration mode. Observe the way the atoms and bonds move for each
mode.
d. Answer question 1 below.
Note:
Sometimes when you select several vibration animations in a row (especially when you
select the animations very fast), the simulation seems to lose track and stops. Just close the
window and click
view
for the molecule again to continue.
1. Name oxygen’s only vibration mode and briefly describe its vibrational motion.
Type your response here:
2
End of preview
© 2013 EDMENTUM, INC.
Unit 4: The Mole Concept
This Unit Activity will help you meet these educational goals:
STEM— You will use online research to understand scientific reasoning. You will get an
insight into STEM careers that are uniquely and personally creative. You will use
mathematics to solve real world scientific problems.
21
st
Century Skills— You will employ online tools for research and analysis, and you will
communicate in written form.
Introduction
In 1811, Amedeo Avogadro proposed that equal volumes of gases at the same
temperature and pressure contain the same number of molecules, regardless of their
chemical nature and physical properties. This came to be known as the Avogadro
hypothesis. This hypothesis went on to become the basis of one of the most widely used
constants in chemical measurements, the Avogadro’s number.
The Avogadro number and the mole concept are essential tools in chemical research,
experiments, and understanding. You can find the composition and formulas of unknown
substances and analyze their properties with the help of molar quantities. In this activity,
you will explore the history of the Avogadro number and the mole concept and analyze the
relationship between them. You will also help solve a hypothetical murder mystery by
finding the formula and properties of an unknown substance found at a crime scene.
__________________________________________________________________________
Directions and Analysis
Task 1:
Avogadro’s number and the mole
Read about the
history of Avogadro’s number
and
the mole
. Then, answer the following
questions. You can type the key search terms below to find more about this topic.
Key search terms:
Avogadro’s number, the mole unit, history of mole
1. Write a short historical account of the discovery of the Avogadro number. In this account,
include the roles of Gay-Lussac, Avogadro, Cannizzaro, and Perrin.
Type your response here:
2. What is the Loschmidt’s number? How is it related to Avogadro’s number?
1
Chemistry
Unit Activity
Type your response here:
3. The mole and Avogadro’s number are now almost synonymous with each other. We say
that one mole of a substance is the amount that contains Avogadro’s number of particles.
However, both concepts were developed independently at different times. Analyze the
theories and definition of both these concepts. Then, explain why it is correct to define a
mole in terms of Avogadro’s number and vice versa.
Type your response here:
Task 2:
The mystery of the unknown substance
A prominent automotive businessman has been murdered in New York. The Crime Scene
Investigation (CSI) team finds a bottle with some clear liquid at the scene of the crime. The
label on the bottle has fallen off. The detectives believe that this bottle belongs to the killer,
who dropped it there in a hurry to get away. Their suspects include the victim’s business rival,
his lawyer, and a theatre actress. The detectives think that if the CSI team can identify the
liquid, they might be able to narrow down the suspects.
One of the CSI technicians has analyzed the liquid using a mass spectrometer and found that
the compound has a molar mass of 58.0714 g. Further analysis has also revealed that the
compound consists of 18 g of carbon, 3 g of hydrogen, and 8 g of oxygen.
Now, help the CSI team nab the killer. Answer the following questions to find the identity of
the unknown substance.
1. What is the percent composition of all the components in the liquid?
Type your response here:
2. What is the empirical formula of the compound?
Type your response here:
3. What is the molecular formula of the unknown liquid?
Type your response here:
2
End of preview
© 2013 EDMENTUM, INC.
Unit 5: Chemical Reactions
This Unit Activity will help you meet these educational goals:
STEM— You will carry out online research to understand scientific reasoning. You will
use mathematics to solve real-world design problems.
21
st
Century Skills— You will employ online tools for research and analysis. You will
communicate using data tables and written explanations.
Introduction
Fireworks! The lights, colors, patterns, and sounds they create in the night sky are always fun
to experience.
But, have you ever stopped to wonder how these fireworks work? How do
they travel up to the sky and then burst into so many different colors? Well, that’s the magic
of Chemistry!
Fireworks were invented around A.D. 1000 by the Chinese. In fact, the basic chemicals used
in a firework haven’t changed much since then. What has evolved and developed into an art
is the way pyrotechnicians use different chemicals to generate amazing effects when a
firework explodes.
In this lesson activity, you will explore more about fireworks and how they work. You will
explore the composition of a firework and find out some of the chemical reactions that occur
in them.
__________________________________________________________________________
Directions and Analysis
Task 1:
Chemical reactions in fireworks
Read about the
components of a firework
and answer the following questions. Then type the
key words
chemical reactions in fireworks
in your search engine to learn more about the
chemical reactions that take place inside a firework.
Key search terms:
how fireworks work, chemical reactions in fireworks
1. What are the different types of chemicals used in a firework?
Type your response here:
2. What role does each type of chemical play in the firework?
Type your response here:
1
Chemistry
Unit Activity
3. What is the composition of the black powder in a firework?
Type your response here:
4. Complete the following table for the reactions that occur when the black powder is ignited.
Type your response here:
Name and
Formula of
Compound
Balanced Chemical
Equation
Type of
Reaction
Mole Ratios of
Reactants to
Products
5. What happens when a firework is ignited?
Type your response here:
6. How are the different colors and designs generated in a firework?
Type your response here:
7. Which chemicals generate the following colors in the fireworks?
Type your response here:
Red:
Blue:
Green:
Yellow:
Purple:
Orange:
Silver:
2
End of preview
© 2013 EDMENTUM, INC.
Unit 6: Kinetic Molecular Theory and Gas Laws
This Unit Activity will help you meet these educational goals:
Science Inquiry— You will learn about the atmosphere by doing online research. You
will also use a simulation to make observations and analyze results related to the
effects of greenhouse gases and other variables on the atmosphere. You will
communicate your results in written form.
21
st
Century Skills—You will employ online tools for research and analysis.
Introduction
The eastern half of the United States is highly urbanized and industrialized. As a
consequence, most of the lakes and streams in this region are acidified. According to the
National Surface Water Survey, about 14% of the lakes in the Adirondack Mountains in New
York and about 12% of streams in the mid-Atlantic Highlands have high acidity levels in their
water and are chronically acidic. This phenomenon is not restricted to the United States.
According to an estimate from the Canadian government, about 14,000 lakes in eastern
Canada are also acidic.
Worldwide, our atmosphere is affected by a host of gasses that are released through natural
events or through human activity. The burning of fossil fuels, such as diesel, gasoline, and
coal, release nitrogen and sulfur oxides into the atmosphere, contributing to acid rain.
Combustion of fossil fuels also contributes to the greenhouse gases in the atmosphere.
How might everyday human activity affect our Earth and the diversity and quality of life here?
To begin to find some answers, you first need to know about the layers and composition of
the Earth’s atmosphere and how it supports life on Earth. Then, you need to understand a bit
more about the mechanics of greenhouse gases and the complex interactions. Both subjects
are based on a deep understanding of kinetic molecular theory and the behavior of gasses.
__________________________________________________________________________
Directions and Analysis
Task 1:
Earth and Its Atmosphere
Earth’s atmosphere works like a shield. Without this shield, our planet would be about 33
degrees Celsius warmer than it is now and would not be able to support life! The atmosphere
blocks most of the harmful rays from the sun and traps heat within so that our days are not
too hot and nights are not too cold.
Read about
Earth and its atmosphere
and use the key search terms to find more information.
Then answer the questions below.
Key search terms:
Earth, atmosphere, layers of atmosphere
1
Chemistry
Unit Activity
1. What is the composition and percentage of the gases in Earth’s atmosphere?
Type your response here:
2. List in ascending order the different layers of atmosphere, their heights, and main
features.
Type your response here:
3. Why are the gases in the troposphere layer denser than the gases in the other layers?
Give reasons for your answer.
Type your response here:
4. How does the kinetic theory of gases explain the weather changes happening in the
troposphere
? You can also research on the Internet using keywords such as
troposphere
,
atmospheric layers
, and
weather changes
.
Type your response here:
2
End of preview
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