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 oh , please help me!

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the mass nos. of 3 isotopees of an element are 10, 12, and 14 units . Their percentage abundance is 80, 15 and 5 respectively. what is the atomic weight of the element?

 

i literally have no idea what to do here, i thought atomic mass and weight were the same thing????sad

 Aug 2, 2017

3+0 Answers

 #1
avatar+2489 
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Hi Rosala,

 

Calculate this by taking the weighted average

 

(80×10+15×12+5×14) / (80+15+5) = 10.5u

 

This is very close to Boron 10.8

 

This should be helpful in understanding.

https://www.khanacademy.org/science/biology/chemistry--of-life/elements-and-atoms/a/atomic-number-atomic-mass-and-isotopes-article

 

 

GA

 Aug 2, 2017
edited by GingerAle  Aug 2, 2017
 #2
avatar+11912 
+1

what does percentage abundance mean?

 

and basically what did you do?

 

check out this boy's answer, he used some other way, im sorta confused?

 

and he even changed the value of the percentages, idk whats happening?

 Aug 2, 2017
edited by rosala  Aug 2, 2017
 #3
avatar+11912 
+3

i got it, thanks gingerale, you are an inspiration to all the monkeys out there........they should get educated too....knowledge is power.......laugh

 Aug 2, 2017

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