Calculate the average atomic mass of lithium using the following data:

Question

Quizplus · Accepted Answer

The atomic mass of lithium includes the contribution of two isotopes: lithium-6 and lithium-7, with abundances of approximately 7.5% and 92.5%, respectively. To calculate the average atomic mass, we need to take into account the mass of each isotope and its relative abundance. 
Using the given data, we can calculate the average atomic mass as follows:

(0.075 x 6.015 amu) + (0.925 x 7.016 amu) = 0.451 amu + 6.486 amu = 6.937 amu

Therefore, the best choice is C)6.94 amu, which is the closest to the calculated value. The other answer choices are either too low or too high compared to the actual value.

Calculate the Average Atomic Mass of Lithium Using the Following