Transition Metal: Silver
Silver has the chemical symbol Ag, and its atomic number is 47; it has the highest electrical conductivity of any element, and the highest thermal conductivity of any metal.
This is hands down my favorite metal, and I have more sterling silver (an alloy of silver consisting here in the US as 92.5% silver and 7.5% copper) jewelry than anyone should possess.
Silver occurs naturally as native silver, and also as an alloy, commonly combined with gold. It is produced as a byproduct of copper, gold, lead, and zinc refining – found commonly in Peru, Mexico (which has been mining silver since 1546 and which is still a major world producer), China, Australia, Chile, and Poland. Silver is used as jewelry, tableware and utensils and coins – it is a symbol of affluence and has been used as currency in all its forms.
Other uses of silver:
Electrical contacts and conductors; soldering compound
In mirrors
In catalysis of chemical reactions
As compound, in photographic film
Was used extensively as a dental amalgam material (for fillings); but this usage has been widely discontinued due to the high mercury content in this process
It has an antimicrobial property and is currently being researched in holistic medicine in the form of silver colloids as an alternative to antibiotics; in WWI it was in fact used as such before the invention of antibiotics.
Silver is highly malleable and is only slightly harder than gold.
There are many other uses for this element, but I will stop here before I end up writing a novel on the subject. I really love silver!
Link Review:
I prefer the link to the Visionlearning website, which has less graphics and more written explanation. I found the explanations to be easier to read and comprehend, and the pictures and graphics were again more helpful to me in understanding the material; the other sites that I was able to access (several of the links didn’t work) had moving graphics that were pretty high tech, but one of them moved too fast to be able to really follow what was happening, and the other one failed to explain what was going on at all.
Sunday, January 25, 2009
Week Two Assignments - Periodic Tables and Atomic Structures
Carbon:
The symbol for carbon is C, and its atomic number is 6; it is a nonmetal
Carbon was known to man from the ancient world, and has been around before recorded history. It exists in all known life forms, and forms the chemical basis of all life on Earth. Because of its affinity for bonding with other small atoms, it forms almost ten million different compounds – the large majority of all known compounds. Carbon is the 4th most abundant element in the universe, and is the 2nd most abundant element in the human body.
Two of the most commonly known allotropes (a variant of molecular structure of an atom with new physical properties) of carbon are diamonds and graphite. The following comparisons are from Wikipedia.com, and they show the differences between the two (essentially, they are polar opposites – and yet, they are both carbon).
Synthetic diamond nanorods are the hardest materials known.
Graphite is one of the softest materials known.
Diamond is the ultimate abrasive.
Graphite is a very good lubricant.
Diamond is an excellent electrical insulator.
Graphite is a conductor of electricity.
Diamond is the best known thermal conductor
Some forms of graphite are used for thermal insulation (i.e. firebreaks and heatshields)
Diamond is highly transparent.
Graphite is opaque.
Diamond crystallizes in the cubic system.
Graphite crystallizes in the hexagonal system.
Amorphous carbon is completely isotropic.
Carbon nanotubes are among the most anisotropic materials ever produced.
Ozone discussion:
....to follow. :)
Review – Elements, Compounds & Mixtures:
Ok, I have to confess, I reviewed this site mainly because the other two were pretty dry and this one had pretty pretty graphics….tee hee. For myself, I appreciate pictures that illustrate a concept which essentially I find difficult – the more variants I have on an explanation will usually help me to understand a bit better; I also find bullet points which explain an idea or concept to be easier to follow and understand – again, backing it up with an illustration being most helpful.
I do suppose that the other two websites ultimately provide more information; but when I am faced with a somewhat overwhelming concept which I am going to have to get my head around, then the simpler approach is definitely the way to go for me. J
The symbol for carbon is C, and its atomic number is 6; it is a nonmetal
Carbon was known to man from the ancient world, and has been around before recorded history. It exists in all known life forms, and forms the chemical basis of all life on Earth. Because of its affinity for bonding with other small atoms, it forms almost ten million different compounds – the large majority of all known compounds. Carbon is the 4th most abundant element in the universe, and is the 2nd most abundant element in the human body.
Two of the most commonly known allotropes (a variant of molecular structure of an atom with new physical properties) of carbon are diamonds and graphite. The following comparisons are from Wikipedia.com, and they show the differences between the two (essentially, they are polar opposites – and yet, they are both carbon).
Synthetic diamond nanorods are the hardest materials known.
Graphite is one of the softest materials known.
Diamond is the ultimate abrasive.
Graphite is a very good lubricant.
Diamond is an excellent electrical insulator.
Graphite is a conductor of electricity.
Diamond is the best known thermal conductor
Some forms of graphite are used for thermal insulation (i.e. firebreaks and heatshields)
Diamond is highly transparent.
Graphite is opaque.
Diamond crystallizes in the cubic system.
Graphite crystallizes in the hexagonal system.
Amorphous carbon is completely isotropic.
Carbon nanotubes are among the most anisotropic materials ever produced.
Ozone discussion:
....to follow. :)
Review – Elements, Compounds & Mixtures:
Ok, I have to confess, I reviewed this site mainly because the other two were pretty dry and this one had pretty pretty graphics….tee hee. For myself, I appreciate pictures that illustrate a concept which essentially I find difficult – the more variants I have on an explanation will usually help me to understand a bit better; I also find bullet points which explain an idea or concept to be easier to follow and understand – again, backing it up with an illustration being most helpful.
I do suppose that the other two websites ultimately provide more information; but when I am faced with a somewhat overwhelming concept which I am going to have to get my head around, then the simpler approach is definitely the way to go for me. J
Sunday, January 11, 2009
Week One Assignments
Hmmmm, my bio. Ok.
I am 47 years old, single mother to a 24 year old son - Jason. I spent most of his childhood and adolescence going to night school and taking community college courses as much as was possible - did some prerequisites to get into nursing school, and then ended up in a trade school to get certified as a medical assistant instead...long story.
After graduation I worked mostly in an administrative capacity for over a decade - did 5 years or so at UCSF, and ended up finally as an office manager in a local hospice. During my last year in the western medical profession, I enrolled in and compelted an accelerated BA program at New College, and graduated in 2006 with my BA in Humanities, with an emphasis on Activism and Social Change.
The job at hospice ended up being a complete nightmare, and once I left there I began to consider returning to school. At the same time, I began to have some serious health problems that western medicine was unable to help me with. I was referred to ACTCM and their community clinic, and one of the interns there encouraged me to consider their program....again, long story sort of short - here I am. :)
Chemistry Quiz Results:
1) I knew that burning wood and crushing a rock were physical changes; I also knew that rusting iron was a chemical change; I was wrong about dissolving sugar in water being a chemical change....
2) I didn't know about milk, or salt, or sugar - :(
I did, however, know that steel was a mixture.
3) I totally guessed that coffee was homogenous and impure....tee hee
4) I was wrong about the boiling of water being a chemical/chemical change.....
I am 47 years old, single mother to a 24 year old son - Jason. I spent most of his childhood and adolescence going to night school and taking community college courses as much as was possible - did some prerequisites to get into nursing school, and then ended up in a trade school to get certified as a medical assistant instead...long story.
After graduation I worked mostly in an administrative capacity for over a decade - did 5 years or so at UCSF, and ended up finally as an office manager in a local hospice. During my last year in the western medical profession, I enrolled in and compelted an accelerated BA program at New College, and graduated in 2006 with my BA in Humanities, with an emphasis on Activism and Social Change.
The job at hospice ended up being a complete nightmare, and once I left there I began to consider returning to school. At the same time, I began to have some serious health problems that western medicine was unable to help me with. I was referred to ACTCM and their community clinic, and one of the interns there encouraged me to consider their program....again, long story sort of short - here I am. :)
Chemistry Quiz Results:
1) I knew that burning wood and crushing a rock were physical changes; I also knew that rusting iron was a chemical change; I was wrong about dissolving sugar in water being a chemical change....
2) I didn't know about milk, or salt, or sugar - :(
I did, however, know that steel was a mixture.
3) I totally guessed that coffee was homogenous and impure....tee hee
4) I was wrong about the boiling of water being a chemical/chemical change.....
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