Question

A pure sample of bromine was vaporized and injected into a mass spectrometer and the data was plotted on the graph below. The mass value for Br-79 is 78 918 amu Find the mass of Br-81.

Answer 1

`m_(Br-81)=80.945amu`

Step-by-step explanation:

Hello,

In this case, since the percent abundance of Br-79 is 51.1% and that of the Br-81 is 48.9 %, we can write:

`m_(Br)=m_(Br-79)*51.1\%+m_(Br-81)*48.9\%`

Taking into account that the mass of bromine from the periodic table is 79.909 amu, the mass of Br-81 turns out:

`m_(Br-81)=(m_(Br)-m_(Br-79)*51.1\%)/(48.9\%) =(79.909amu-78.918*0.511)/(0.489) \\\\m_(Br-81)=80.945amu`

Best regards.