Nitrogen average atomic mass

The average atomic mass of N is 14.0067 amu. There are two isotopes which contribute to this average (14.00307 amu) and (15.00011 amu). Calculate the percentage of atoms in a sample of naturally occurring nitrogen. 

Practice Problem B The average atomic mass of nitrogen is 14.0067. The atomic masses of the two stable isotopes of nitrogen, N and - N, are 14.003074002 and 15.00010897 amu, respectively. Use this information to determine the percent abundance of each nitrogen isotope. 

The atomic mass of an element is the average mass of all atoms of the element relative to carbon-12 taken as exactly 12. Since atomic masses are relative quantities, they can be expressed without units. Or atomic masses may be given in atomic mass units. For example, an atomic mass of 14.0067 for nitrogen means that the average mass of all nitrogen atoms is 14.0067/12 as great as the mass of the carbon-12 isotope and is also 14.0067 u. 

Comment Because of its smaller mass, a helium atom, on the average, moves about 2.6 times faster than a nitrogen molecule at the same temperature (1360 515 =... 

The average mass of nitrogen is 14.01 amu. The appropriate equivalence statement is 1 N atom = 14.01 amu, which yields the conversion factor we need ... 

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