Multiple Choice
A sample of chlorine weighing 20.57 grams contains two naturally occurring isotopes: Cl-35 and Cl-37. If the atomic masses are 34.9689 amu for Cl-35 and 36.9659 amu for Cl-37, and the natural abundance of Cl-35 is approximately 75.78%, what is the mass of Cl-35 in the sample?
