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4 votes
A mass spectrum reveals that a molecule has a (M)+ peak at

m/z=196 and its relative abundance is 27.2% The (M+1)+ peak is 3.9%
abundant.
Calculate the number of carbon atoms in the molecule

1 Answer

7 votes

Final answer:

To calculate the number of carbon atoms in the molecule, we need to consider the relative abundance of the (M)+ peak and the (M+1)+ peak in the mass spectrum. The (M)+ peak at m/z=196 has a relative abundance of 27.2%, while the (M+1)+ peak is 3.9% abundant. Using this information, we can determine the number of carbon atoms in the molecule to be approximately 3.51.

Step-by-step explanation:

To calculate the number of carbon atoms in the molecule, we need to consider the relative abundance of the (M)+ peak and the (M+1)+ peak in the mass spectrum. The (M)+ peak at m/z=196 has a relative abundance of 27.2%, while the (M+1)+ peak is 3.9% abundant.

The (M)+ peak represents the molecular ion (a molecule with a positive charge), which includes the carbon atoms. The (M+1)+ peak represents the molecular ion with one additional neutron, which is due to the presence of a ^{13}C isotope.

Since the (M+1)+ peak is 3.9% abundant, we can conclude that the molecule contains 3.9% of carbon atoms with a mass number of 13, (^{13}C).

Now, we can calculate the number of carbon atoms in the molecule as follows:

Number of carbon atoms = (3.9% / 1.11%) x 100%

Number of carbon atoms = 3.51

Therefore, the molecule contains approximately 3.51 carbon atoms.

answered
User Jesse Kinsman
by
8.5k points
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