Answer:
14.01 amu
Step-by-step explanation:
Step 1: Given data
Isotope Atomic mass (am) Abundance (ab)
¹⁴N 14.00307 amu 99.64% (0.9964)
¹⁵N 15.0001 amu 0.36% (0.0036)
Step 2: Calculate the average atomic mass (aam) of nitrogen
We will use the following expression.
aam = ∑ am × ab
aam = 14.00307 amu × 0.9964 + 15.0001 amu × 0.0036 = 14.01 amu