which isotopes occur in greater cbundance?
2006-10-16 08:58:10 · 6 answers · asked by nikki 1 in Science & Mathematics ➔ Chemistry
The average atomic mass of an element is calculated by taking a weighted average of the atomic masses of each of the element's naturally occurring isotopes.
In the case of Boron, there are two naturally occurring isotopes, Boron-10 and Boron-11 with atomic masses of 10 and 11 amu respectively.
To solve this problem, lets assume that Boron-10 occurs at a natural percentage of x%, meaning that Boron-11 would occur at a percentage of 100-x%.
To find the average atomic mass, which we know to be 10.81 amu, add the atomic masses of each isotope multiplied by its percentage occurrence,
10.81 amu * 100% = (x * 10 amu) + ((100 - x) * (11 amu))
Multiply everything out and we get,
1081 = 10x + 1100 - 11x
-19 = -x
x = 19
Since x = 19%, 100 - 1 must equal 81%.
Therefore, the natural percent occurrence of Boron-10 is 19% and Boron-11 is 89%.
Checking this,
http://www.webelements.com/webelements/elements/text/B/isot.html
We find this answer is very close to the actual occurrences of the natural isotopes of Boron, the difference is due to the slight rounding which were used in this question to make the math easier.
2006-10-16 09:10:12 · answer #1 · answered by mrjeffy321 7 · 0⤊ 0⤋
Elemental Boron
2016-11-12 08:17:41 · answer #2 · answered by ? 4 · 0⤊ 0⤋
It's related to their abundances, it means for calulating the average atomic mass of Boron we should consider them and accorrding to this atomic mass, Boron-11 has graeter abundance than other isotope
2006-10-16 09:25:09 · answer #3 · answered by anahita8642 1 · 0⤊ 0⤋
( (1-y)* 10.013) + (y* 11.009) = 10.81 amu
10.013 – 10.013y + 11.009y = 10.81
0.996y = .797
y = .797 / 0.996 = 0.800
y = 80% So Boron 11 is in abundance.
2006-10-16 09:32:25 · answer #4 · answered by SMG 3 · 0⤊ 0⤋
DOOFUS! many human beings defined this to you for the chlorine question...we are no longer right here to try this for you. that's a theory a 2d grader could comprehend...which ever that's closer to! some truthfully everyone seems to be some dumb....
2016-12-26 20:52:37 · answer #5 · answered by Anonymous · 0⤊ 0⤋
well its pretty obvious it has to be 11 and you dont have to do a page of calcualtions to verify that.
2006-10-20 03:10:12 · answer #6 · answered by Anonymous · 0⤊ 0⤋