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Atomic weights of 10 elements on periodic table about to make an historic change
Eureka Alert ^ | 15 Dec 2010 | Leanne Yohemas

Posted on 12/15/2010 5:23:20 PM PST by smokingfrog

For the first time in history, a change will be made to the atomic weights of some elements listed on the Periodic table of the chemical elements posted on walls of chemistry classrooms and on the inside covers of chemistry textbooks worldwide.

The new table, outlined in a report released this month, will express atomic weights of 10 elements - hydrogen, lithium, boron, carbon, nitrogen, oxygen, silicon, sulfur, chlorine and thallium - in a new manner that will reflect more accurately how these elements are found in nature.

"For more than a century and a half, many were taught to use standard atomic weights — a single value — found on the inside cover of chemistry textbooks and on the periodic table of the elements. As technology improved, we have discovered that the numbers on our chart are not as static as we have previously believed," says Dr. Michael Wieser, an associate professor at the University of Calgary, who serves as secretary of the International Union of Pure and Applied Chemistry's (IUPAC) Commission on Isotopic Abundances and Atomic Weights. This organization oversees the evaluation and dissemination of atomic-weight values.

Modern analytical techniques can measure the atomic weight of many elements precisely, and these small variations in an element's atomic weight are important in research and industry. For example, precise measurements of the abundances of isotopes of carbon can be used to determine purity and source of food, such as vanilla and honey. Isotopic measurements of nitrogen, chlorine and other elements are used for tracing pollutants in streams and groundwater. In sports doping investigations, performance-enhancing testosterone can be identified in the human body because the atomic weight of carbon in natural human testosterone is higher than that in pharmaceutical testosterone.

(Excerpt) Read more at eurekalert.org ...


TOPICS: Canada; News/Current Events
KEYWORDS: chemistry; elements; science
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To: BenKenobi
Well sure, yours does now. Mine doesn’t. :) Had it for a long time.

OK. If you will go with the flow for a few minutes I will also. One step at a time.

What does your chart say for the atomic mass of Chlorine?

121 posted on 12/15/2010 9:55:35 PM PST by SeeSac
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To: SeeSac

Mine has both. :)

Old school.


122 posted on 12/15/2010 9:56:25 PM PST by BenKenobi
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To: SeeSac

34.987


123 posted on 12/15/2010 9:58:26 PM PST by BenKenobi
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I assume your table gives 35.453 since that is what you have been quoting.

Now (from wikipedia):

“Chlorine has a wide range of isotopes. The two stable isotopes are 35Cl (75.77%) and 37Cl (24.23%). Together they give chlorine an atomic weight of 35.4527 g/mol.”

thus if your ‘old’ table gives 35.453 it is giving the ELEMENTAL mass which is based on the ratio of isotopes.


124 posted on 12/15/2010 9:58:43 PM PST by SeeSac
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To: BenKenobi
34.987

That must be incorrect. Earlier you stated it was 35.453.

125 posted on 12/15/2010 10:03:04 PM PST by SeeSac
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To: SeeSac

Wikipedia is God.


126 posted on 12/15/2010 10:03:17 PM PST by BenKenobi
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To: SeeSac

For the relative mass yes.

The atomic mass is different. You asked me what it stated for the atomic mass.


127 posted on 12/15/2010 10:04:33 PM PST by BenKenobi
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To: Gene Eric; smokingfrog
Thanks for the ping, Gene Eric.

For the first time in history, a change will be made to the atomic weights of some elements listed on the Periodic table of the chemical elements posted on walls of chemistry classrooms and on the inside covers of chemistry textbooks worldwide.

The writer of this press release got it wrong. The doc got it right. It's just the periodic table of the elements.

128 posted on 12/15/2010 10:06:43 PM PST by neverdem (Xin loi minh oi)
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To: decimon

Me too. I noticed a tank truck of hydrogen going up hill just a wee bit faster.


129 posted on 12/15/2010 10:22:25 PM PST by MontaniSemperLiberi (Moutaineers are Always Free)
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To: SoftwareEngineer; Mikey_1962
The Zero was invented by South Indians.

Misplaced and factually incorrect didacticism is ill becoming, and in this case, even libelous.

The father of Zero was an Islamic Muslim, as was a good part of that family.

His stepfather was also Muslim.

Islamic Muslims are indeed responsible for Zero; Indians had nothing to do with him.

130 posted on 12/15/2010 11:07:27 PM PST by ApplegateRanch (Islam: A Satanically Transmitted Disease spread by unprotected intimate contact with the Koranus)
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To: ApplegateRanch

Sir/Madam,

You have wronged me!

I said “The Zero” and not just plain “Zero”.

As we all know.. our current President is not even the original or the best Zero.

So, THE Zero, still stands proud and non Islamic.

:)


131 posted on 12/15/2010 11:39:37 PM PST by SoftwareEngineer
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To: Erasmus
That's right. When the elements are build up via fusion, energy, the equivalent of mass, is released. The isotopic mixes I mentioned are in the other elements, not the reference element, Carbon.
132 posted on 12/16/2010 4:31:48 AM PST by Aevery_Freeman (Fear God and Government - especially when one tries to become the other!)
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To: chemengineer42

Good point.


133 posted on 12/16/2010 5:26:34 AM PST by WayneS (Enlightened statesmen will not always be at the helm. -- James Madison)
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To: Mikey_1962
Zero was invented by the Islamic Arabs btw.

I thought he was "invented" by an African Arab.

134 posted on 12/16/2010 5:29:32 AM PST by WayneS (Enlightened statesmen will not always be at the helm. -- James Madison)
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To: BenKenobi
Whatever. Do you still stand behind the erroneous statements you made that started this?

“The atomic mass of CL 35 is 35.453 as a result of CL 35 having 17 protons and 18 neutrons”

“CL 35 the 35 means that it has 17 protons and 18 neutrons. Why isn’t this 35.000 instead of 35.453? Because the mass of the neutron is the combined mass of a proton plus an electron. That’s where you get the extra bit on.”

135 posted on 12/16/2010 5:34:57 AM PST by SeeSac
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To: Raymann

How far away do any other bodies need to be in order for the body in question to be considered to have “cleared the heighborhood around its orbit”?

I’m curious, because it makes me wonder how they can judge Earth to have “cleared the neighborhood around its orbit” when it has this ‘moon’ thing following it around everywhere.


136 posted on 12/16/2010 5:41:06 AM PST by WayneS (Enlightened statesmen will not always be at the helm. -- James Madison)
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To: BenKenobi

How did you standardize the acid solutions (i.e. how do you know what their molarities are)?


137 posted on 12/16/2010 10:26:05 AM PST by Hoodat (Yet in all these things we are more than conquerors through Him who loved us. - (Rom 8:37))
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To: Hoodat

There’s 4 variables.

Concentration X, Concentration Y, Crystal Z and Crystal W

Adding concentration X to Z and W gives me two equations:

X+Z -> XZ
X+W -> XW

Adding concentration Y to Z and W gives me two more equations:

Y+Z -> YZ
Y+W -> YW.

I can then use the systems of equations to solve for all 4 variables, once I know the concentration of acid required to dissolve YW and YW. To keep it easier, I make sure I have the exact same amount of both Z and W, and I keep the concentration in the standard solution the same. The only thing that will change between the two is the volume of the acid.


138 posted on 12/16/2010 3:28:29 PM PST by BenKenobi
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To: BenKenobi

How did you standardize the acid solutions (i.e. how do you know what their molarities are)?


139 posted on 12/16/2010 3:37:27 PM PST by Hoodat (Yet in all these things we are more than conquerors through Him who loved us. - (Rom 8:37))
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To: Hoodat

Obviously you didn’t bother reading my answer or you’d already know. Bye.


140 posted on 12/16/2010 3:42:16 PM PST by BenKenobi
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