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Chemistry
Unit Activity
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
...
STEM— You will use simulations and online research to understand scientific
reasoning
...
st
21 Century Skills— You will employ online tools for research and analysis
...
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
...
That’s generally a good thing,
preventing wild temperature swings on Earth between night and day
...
That
wouldn’t necessarily be a good thing
...
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
...
__________________________________________________________________________
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
...
1
...
Type your response here: The basic physics of the greenhouse effect is simple
...
Allow short wave radiation from the Sun to pass
through and block some of the longer wave radiation from the Earth from escaping
into space
...
However, since humans
started to burn fossil fuels, the atmospheric concentration of CO2 has been
increasing, causing the Earth to warm
...
If this is not stopped, sea levels may rise, causing millions of
people to lose their homes
...
How is the greenhouse effect related to global warming?
Type your response here: Global warming is the direct result of the greenhouse
effect
...
So the greenhouse effect is essential for human existence
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The present average global temperature is just about right for human comfort and
civilization
...
3
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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
...
Based on 1990 concentrations, carbon dioxide is said
to be responsible for almost 60% of the total greenhouse effect when efficiency and
concentration are considered
...
Another cause of CO2 increase is the destruction of large areas of trees that leads to a
reduction in use of carbon dioxide for photosynthesis
...
It contributes to a little over
10% of the total greenhouse effect based on current concentrations
...
Nitrous oxide also occurs in low concentrations relative to carbon dioxide, but it is 230
times more efficient as a greenhouse gas
...
The primary anthropogenic sources are
fossil fuel combustion, fertilizers, and deforestation
...
They come solely from anthropogenic sources such as the
production and/or use of foams, aerosols, refrigerants, and solvents
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As a result, they
contribute to approximately 25% of the total greenhouse effect based on 1990
concentrations
...
While carbon
dioxide and methane are greenhouse gases, oxygen is not
...
On the top menu, click entry level to reduce the total number of compounds
...
On the periodic table, select molecules by clicking the individual atoms
that form them (the molecules)
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Click O, wait for a few seconds, and then click O again
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Scroll below to see the list of molecules the O-O bond form
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c
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In the “show vibration” box, select each
available vibration mode
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d
...
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
...
1
...
Type your response here: The website won’t work on my computer
...
Close the simulation window for oxygen and return to the Cool Molecules Explore
page
...
Find and view carbon dioxide (CO2) and
view all the available vibrational modes of the molecule
...
Note: A molecule may have more than one way it can vibrate in each mode (a “state
...
Record the number of unique possible states for each
mode in the table
...
Close the simulation window for oxygen and return to the Cool Molecules Explore
page
...
In the
table below, record the names of its vibrational modes and describe the vibration of the
molecule in each mode
...
Type your response here:
Vibration
Number of
Mode
States in the
Description
4
Mode
4
...
Type your response here:
5
...
Points possible:
Greenhouse Effect: 5 points maximum
Vibration Modes of Gas Molecules: 5 points maximum
Greenhouse Effect
5 points
Explain the greenhouse effect
List and describe the major
greenhouse gases and their impact
Describe the behavior of a molecule of
a greenhouse gas when exposed to
sun’s radiation
Vibration Modes of Gas Molecules
5 points
Observe and describe the vibration
mode of oxygen molecule
...
Observe and describe the vibration
modes and states of methane
molecule
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Self-Checked Activity: For Advanced Understanding
Note: This section may be optional; follow your instructor’s directions
...
The test items will challenge your
knowledge of the unit concepts, help you tie different concepts together, and help you gain
confidence in addressing written response test items
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Answer all parts of the question thoughtfully and concisely to the extent of your
ability
...
For Scoring: Scoring Guidelines
See Question 5
6