Monday, January 28, 2008
Molecular Modeling
I reviewed most of this week's links, struggling to find one that made any sense at all to me. Some moved too fast; two dimensions didn't do much to help me; one site depicted many different tri-colored blobs. But, I liked the water model. The depiction of the hydrogen molecules in motion, bonding and breaking (at a pace that I could actually watch), reminded me of irregular waves caused by raindrops splashing in a puddle. I could connect the notion of the weak hydrogen bonds breaking and reforming with an image of water droplets splashing apart in a puddle and then rebonding (becoming part of the puddle).
Sunday, January 27, 2008
Carbon: A picture is worth a thousand words
Go to the link below to see the structure of carbon atoms in graphite, diamonds, and fullerenes.
http://www.edinformatics.com/interactive_molecules/carbon_jmol.htm
http://www.edinformatics.com/interactive_molecules/carbon_jmol.htm
Rhenium in Transition
Did you know that rhenium (pronounced ri-neum) was the next-to-last naturally occurring element to be discovered?
Its name derives from the Latin term rhemus meaning Rhine. Those who know their world geography will deduce from its name that it was discovered in . . . Germany, in the year 1925.
Rhenium is clingy and reclusive. It is not found free; rather, it is detected in ores, like platinum and porphyry copper, and minerals, like columbite. It's favorite companion is molybdenum. Rhenium is recovered as a byproduct from roasting molybdenum concentrates.
Recovering rhenium is an expensive process, which lends to rhenium's distinction of making the list of the top 10 most expensive transition metals. During 2006, average rhenium metal price was a whopping $1,170 per kilogram, but it rose as high as $5,000 per kilogram when Kazakhstan refused to supply it to the U.S. for several months!
Rhenium is a component of platinum-rhenium catalysts that are used primarily in producing lead-free, high-octane gasoline and in high-temperature superalloys used for jet engine components.
The largest producer of rhenium has always been Chile. Kazakhstan has become the second largest producer. The United States relies heavily on rhenium imports, as it produces rhenium from only six mines in the U.S.: Two in Arizona and one each in Montana, Nevada, New Mexico and Utah.
Its name derives from the Latin term rhemus meaning Rhine. Those who know their world geography will deduce from its name that it was discovered in . . . Germany, in the year 1925.
Rhenium is clingy and reclusive. It is not found free; rather, it is detected in ores, like platinum and porphyry copper, and minerals, like columbite. It's favorite companion is molybdenum. Rhenium is recovered as a byproduct from roasting molybdenum concentrates.
Recovering rhenium is an expensive process, which lends to rhenium's distinction of making the list of the top 10 most expensive transition metals. During 2006, average rhenium metal price was a whopping $1,170 per kilogram, but it rose as high as $5,000 per kilogram when Kazakhstan refused to supply it to the U.S. for several months!
Rhenium is a component of platinum-rhenium catalysts that are used primarily in producing lead-free, high-octane gasoline and in high-temperature superalloys used for jet engine components.
The largest producer of rhenium has always been Chile. Kazakhstan has become the second largest producer. The United States relies heavily on rhenium imports, as it produces rhenium from only six mines in the U.S.: Two in Arizona and one each in Montana, Nevada, New Mexico and Utah.
Monday, January 14, 2008
Cultural Influence of Chemistry: Natural Disasters
How much do we really understand the effects of natural disasters and global warming?
Through experience, the human race understands the present effects of natural disasters and global warming. I believe that we do not grasp the scale of the future effects of natual disasters and global warming. We seek to understand the causes during and after we have experienced the effect, which captures the media spotlight. After we have addressed the immediate effect, we tend to lose our interest in preventing the next disaster until it is upon us once again.
I remember taking an Environmental Issues class at Berkeley in 1988. Global warming was discussed at length. Once I left that classroom, I heard very little about global warming until Al Gore's movie gave rise to heated debate between groups of my friends.
The geologists, chemists, and biologists who are among my friends have expressed no uncertainty about the effects of global warming and the need to take action. On the other hand, the majority of my friends who lack science backgrounds have been skeptical about the Al Gore movie. In fact, some of these people expressed outrage when their children came home from school talking about what they had learned about global warming.
I remember my parents reacting with the same skepticism in the late 197o's and early 1980's when I came home from school convinced that we needed to rely on alternative energy sources, particularly solar power, instead of petroleum. The economic incentives for using alternative energy all but disappeared during the Reagan era and have not re-emerged yet in any meaningful way.
These experiences have led me to conclude that there is no shortage of understanding in the scientific community about global warming; however, many of us hear what we want to hear, and we don't ask questions when we suspect that we won't like the answers. Our difficulties are not in failure to understand, but rather, in our failure to accept and act.
Through experience, the human race understands the present effects of natural disasters and global warming. I believe that we do not grasp the scale of the future effects of natual disasters and global warming. We seek to understand the causes during and after we have experienced the effect, which captures the media spotlight. After we have addressed the immediate effect, we tend to lose our interest in preventing the next disaster until it is upon us once again.
I remember taking an Environmental Issues class at Berkeley in 1988. Global warming was discussed at length. Once I left that classroom, I heard very little about global warming until Al Gore's movie gave rise to heated debate between groups of my friends.
The geologists, chemists, and biologists who are among my friends have expressed no uncertainty about the effects of global warming and the need to take action. On the other hand, the majority of my friends who lack science backgrounds have been skeptical about the Al Gore movie. In fact, some of these people expressed outrage when their children came home from school talking about what they had learned about global warming.
I remember my parents reacting with the same skepticism in the late 197o's and early 1980's when I came home from school convinced that we needed to rely on alternative energy sources, particularly solar power, instead of petroleum. The economic incentives for using alternative energy all but disappeared during the Reagan era and have not re-emerged yet in any meaningful way.
These experiences have led me to conclude that there is no shortage of understanding in the scientific community about global warming; however, many of us hear what we want to hear, and we don't ask questions when we suspect that we won't like the answers. Our difficulties are not in failure to understand, but rather, in our failure to accept and act.
Quiz results
My answers to Richard Banks' quiz:
1. Classify the following as either a chemical or physical change.
Burning wood : physical
Crushing a rock : physical
Dissolving sugar in water : physical
The rusting of iron: chemical
2. Classify the following as to whether or not they are pure substances or mixtures.
milk: mixture
table salt : mixture
sugar : pure
steel : mixture
3. A cup of black coffee is considered to be __?__ and a/an __?__ substance.
(a) homogeneous…..pure
(b) homogeneous…..impure
(c) non-homogeneous…pure
(d) non-homogeneous…impure
I chose non-homogenous impure first. Apparently, that is not necessarily correct, but I can't say that I understand why. Perhaps I assumed a cup of brewed coffee and the question referred to a cup of coffee beans? Is that the difference?
4. The boiling of water is considered to be a __?__ change and the temperature at which water boils is considered to be a __?__ property. Answer: (d)
(a) chemical…..chemical
(b) chemical…..physical
(c) physical…..chemical
(d) physical…..physical
1. Classify the following as either a chemical or physical change.
Burning wood : physical
Crushing a rock : physical
Dissolving sugar in water : physical
The rusting of iron: chemical
2. Classify the following as to whether or not they are pure substances or mixtures.
milk: mixture
table salt : mixture
sugar : pure
steel : mixture
3. A cup of black coffee is considered to be __?__ and a/an __?__ substance.
(a) homogeneous…..pure
(b) homogeneous…..impure
(c) non-homogeneous…pure
(d) non-homogeneous…impure
I chose non-homogenous impure first. Apparently, that is not necessarily correct, but I can't say that I understand why. Perhaps I assumed a cup of brewed coffee and the question referred to a cup of coffee beans? Is that the difference?
4. The boiling of water is considered to be a __?__ change and the temperature at which water boils is considered to be a __?__ property. Answer: (d)
(a) chemical…..chemical
(b) chemical…..physical
(c) physical…..chemical
(d) physical…..physical
Periodic Table Links
I visited each of the Periodic Table links identified on our class blog.
The "chemical elements" link humbled me: If this is a reference for elementary, middle school, and high school students, how did I ever make it through graduate school?
The "interactive" link was helpful. It's convenient to have many different (and colorful) ways to look at the information that is captured on the periodic tables.
The "spiral" link looked trippy and seemed to have some logic to it. Unfortunately, I have no idea what the logic is.
My favorite, by far, was the "memory" link by John Pratt. If I had to memorize all of the elements on the periodic table, I would use this tool. The pictures are easily identifiable, and the explanations of how the elements are linked to the pictures are easy to recall.
The "quiz" link was of no help. I scored 50% on the quiz but learned nothing about electron/neutron/ion counts and how they relate to atomic weight.
The "game" link: Love it!!! I could play this game forever with my kids, and eventually we would all learn the elements of the periodic table. I felt very competent when I received a 10/10 score on a couple of the quizzes and was able to e-mail those test results to my husband!! I did notice while playing the naming game that I was able to receive an artificially inflated score because the quiz asked me three times to name "H". Because I was able to type "hydrogen" correctly all three times, I earned 3/3 points. I probably would have received a lower overall score, if I had to name three different elements instead.
The "rejected" link: What can I say? I like to side with the underdogs, and agree that grenadine belongs on the periodic table.
The "chemical elements" link humbled me: If this is a reference for elementary, middle school, and high school students, how did I ever make it through graduate school?
The "interactive" link was helpful. It's convenient to have many different (and colorful) ways to look at the information that is captured on the periodic tables.
The "spiral" link looked trippy and seemed to have some logic to it. Unfortunately, I have no idea what the logic is.
My favorite, by far, was the "memory" link by John Pratt. If I had to memorize all of the elements on the periodic table, I would use this tool. The pictures are easily identifiable, and the explanations of how the elements are linked to the pictures are easy to recall.
The "quiz" link was of no help. I scored 50% on the quiz but learned nothing about electron/neutron/ion counts and how they relate to atomic weight.
The "game" link: Love it!!! I could play this game forever with my kids, and eventually we would all learn the elements of the periodic table. I felt very competent when I received a 10/10 score on a couple of the quizzes and was able to e-mail those test results to my husband!! I did notice while playing the naming game that I was able to receive an artificially inflated score because the quiz asked me three times to name "H". Because I was able to type "hydrogen" correctly all three times, I earned 3/3 points. I probably would have received a lower overall score, if I had to name three different elements instead.
The "rejected" link: What can I say? I like to side with the underdogs, and agree that grenadine belongs on the periodic table.
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