Problem: The mass spectrum of bromine (Br2) consists of three peaks with the following characteristics:How do you interpret these data?

🤓 Based on our data, we think this question is relevant for Professor Staff's class at UGA.

FREE Expert Solution

Mass Spectrometry allows you to determine the molecular weight of an unknown compound through its vaporization and ionization. 

Mass spectrometer is used to determine the mass to charge ratio of an unknown compound. 


Divide the given masses into two to determine the possible isotopes of Br:

Peak 1: m Br2 = 157.84

m Br = 157.84/2 

m1 Br = 78.92

Peak 2: m Br2 = 159.84

m Br = 159.84/2 

m2 Br = 79.92

Peak 3: m Br2 = 161.84

m Br = 161.84/2 

m3 Br = 80.92


From the spectrum, we can say that Br has 2 isotopes. One of the three peaks is a combination of the two isotopes. Knowing this, we can determine the isotopes:

m Br2 = m1 Br + m2 Br

m Br2 = 78.92 + 79.92

m Br2 = 158.84 → not in the peak (one of the mass is not an isotope)

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Problem Details

The mass spectrum of bromine (Br2) consists of three peaks with the following characteristics:

How do you interpret these data?

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Our data indicates that this problem or a close variation was asked in Chemistry: An Atoms First Approach - Zumdahl 2nd Edition. You can also practice Chemistry: An Atoms First Approach - Zumdahl 2nd Edition practice problems.