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# Chemistry RAM help Watch

1. Can someone help me with this question!

A mass spectrum of a sample of antimony showed two peaks at m/z= 120 and m/z= 122. The relative atomic mass of this sample of antimony is 121.3. Use these data to calculate the ratio of the relative abundances of the two isotopes.
2. Just did it- pic will follow
3. (Original post by ohmickeyursofine)

Posted from TSR Mobile
Your answer is wrong. 122 must be more abundant than 120 as the relative atomic mass is 121.3
4. (Original post by Naya104)
Can someone help me with this question!

A mass spectrum of a sample of antimony showed two peaks at m/z= 120 and m/z= 122. The relative atomic mass of this sample of antimony is 121.3. Use these data to calculate the ratio of the relative abundances of the two isotopes.
121 = 50:50 abundance

Therefore, each 0.5 is worth 25% abundance
Therefore, each 0.05 is worth 2.5% abundance

121 + 0.05 x 6 = 121.3

6 0.05s therefore 2.5 x 6 = 15%

50 + 15 = 65

Ratio is 35:65
5. Oh sorry woops it's been a long day- did it the wrong way round, it would be 120x and 122(100-x)
6. The other method works just as good- at least someone noticed the mistake!
7. Thank you

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