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# How to calculate the relative atomic mass and abundances of an element? watch

1. Using mass spectra, calculate the Ar of the following element:
Given that lead has four isotopes, 204Pb with an abundance of 23.6%. 206Pb with an abundance of 23.6%, 207Pb with an abundance of 22.6% and 208Pb with an abundance of 52.3%.

Isotopic mass and Relative abundance (percentage)
204.0 = 1.55%
206.0 = 23.6%
207.0 = 22.6%
208.0 = 52.3%

Ar = ?
2. do (204 x 23.6) + (206 x 23.6) +(207 x 22.6) + (208 x 52.3) / 100
3. (Original post by khxtijah)
do (204 x 23.6) + (206 x 23.6) +(207 x 22.6) + (208 x 52.3) / 100
Makes sense now. Thanks for your help

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