Forgot your password?
typodupeerror

Comment: Why not look in Wikipedia first? (Score 1) 147

by astrobotanic (#34558860) Attached to: Atomic Weight Not So Constant
The IUPAC definition[1] of atomic weight is: An atomic weight (relative atomic mass) of an element from a specified source is the ratio of the average mass per atom of the element to 1/12 of the mass of an atom of 12C. The definition deliberately specifies "An atomic weight...", as an element will have different atomic weights depending on the source. For example, boron from Turkey has a lower atomic weight than boron from California, because of its different isotopic composition.[6][7] Nevertheless, given the cost and difficulty of isotope analysis, it is usual to use the tabulated values of standard atomic weights which are ubiquitous in chemical laboratories. http://en.wikipedia.org/wiki/Atomic_weight

"I got everybody to pay up front...then I blew up their planet." "Now why didn't I think of that?" -- Post Bros. Comics

Working...