Wednesday, 13 February 2013

1.12 calculate the relative atomic mass of an element from the relative abundances of its isotopes

Relative atomic mass is the average weight of an atom of an element. There is variation in the weight due to the fact that there are different isotopes with in an element. (Different isotopes have different weights due to less or more neutrons.)

It is calculated like this:
(% of isotope x its mass) + (% of isotope x its mass) / 100

e.g for chlorine
75% of all chlorine has a mass of 35. 25% of all chlorine has a mass of 37.
(75 × 35) + (25 × 37)100
2625 + 925100
= 35.5

16 comments:

  1. (Different isotopes have different weights due to less or more protons.)
    its not protons, its neutrons :P

    ReplyDelete
  2. Shouldn't it be 75% and 25%?

    ReplyDelete
  3. 75% of all chlorine has a mass of 25% of all chlorine has a mass of 37. (makes no sense needs to be...)
    75% of all chlorine has a mass of 35. 25% of all chlorine has a mass of 37.

    ReplyDelete
  4. Sorry this post has been laced with mistakes, not sure what was going on when I wrote it ;P Thank you all for the help!

    ReplyDelete
  5. This comment has been removed by the author.

    ReplyDelete

  6. Cotton Affairs is an Australian owned family business founded in Sydney, Australia in 1995.
    It specialises in designing, sourcing and bringing to market a wide diversity of textile homeware products.


    doona cover set

    ReplyDelete
  7. i love this blog thank you so much hannah you are my saviour

    ReplyDelete
  8. How do you find out the percentage of isotopes? Or is it always been given in the questions?

    ReplyDelete
  9. The Chemistry Syllabus has changed…

    Here is a New blog for the 2017 Syllabus:

    https://igcse-chemistry-2017.blogspot.hk/

    ReplyDelete
  10. Hi

    Are you on the path to ultimate life success?

    Why leave it to chance? I highly recommend that you take this 60 second quiz and then check out your customised report that comes from it.

    ==> 60 Second Life Success Quiz (and personalised report)

    I was shocked at how accurate the results were for me when I tried this quiz myself and I’m sure you’ll be impressed too.

    Your report reveals things you need to know, customised for you based on your responses, so that you can manifest for yourself a life of wealth, love, health, success and more!

    ==> Go here for the 60 second life success quiz (and personalised report)

    Enjoy and go well!

    Kind regards,








    .

    ReplyDelete