Final answer:
The average atomic mass of a mixture of Nitrogen isotopes with abundances 95% N and 5% another isotope of N (assumed to be 15N based on natural abundance) can be calculated using the weighted average formula. The result of the calculation is 14.07 amu. Option C is correct..
Step-by-step explanation:
To determine the average atomic mass of the mixtures of Nitrogen isotopes, you would use the relative abundance and the atomic masses of each isotope. Nitrogen has two common isotopes, 14N and 15N. These isotopes have atomic masses of approximately 14 amu and 15 amu, respectively. Although the question doesn't specify which isotopes the percentages belong to, these are the only stable isotopes of nitrogen, and the most common isotope is 14N.
The formula for calculating the average atomic mass (AAM) is as follows:
AAM = (fraction of isotope 1 × atomic mass of isotope 1) + (fraction of isotope 2 × atomic mass of isotope 2) + ... for all isotopes.
In this case, assuming the question refers to 95% 14N, 3% 15N, and 2% 15N (as the other 2% must be associated with an isotope and by default would also be 15N due to its low natural abundance), the calculation would look like this:
AAM = (0.95 × 14 amu) + (0.05 × 15 amu)
AAM = (13.3 amu) + (0.75 amu)
AAM = 14.05 amu, which can be rounded to 14.07 amu when considering significant figures.
Thus, the correct answer is C) 14.07 amu..