Question

calculate the average atomic mass of carbon if 98.90% of the atoms are c-12 (12.000000 amu) and 1.100% are c-13 atoms (13.003354 amu). type in your answer using 2 decimal places.
$m_a$ for carbon = \boxed{} amu

Explanation:

Step1: Convert percentages to decimals

For C - 12: \(98.90\% = 0.9890\)
For C - 13: \(1.100\% = 0.01100\)

Step2: Calculate contribution of each isotope

Contribution of C - 12: \(0.9890\times12.000000 = 11.868\)
Contribution of C - 13: \(0.01100\times13.003354 = 0.143036894\)

Step3: Sum the contributions

Average atomic mass \(= 11.868+ 0.143036894=12.011036894\approx12.01\) (rounded to 2 decimal places)

Answer:

12.01