Lithium forms compounds which are used in dry cells and storage batteries and in high-temperature lubricants. It has two naturally occurring isotopes, ⁶Li (isotopic mass = 6.015121 amu) and ⁷Li (isotopic mass = 7.016003 amu). Lithium has an atomic mass of 6.9409 amu. What is the percent abundance of lithium-6? A)92.50% B)86.66% C)46.16% D)7.503% E)6.080%

Question

Quizplus · Accepted Answer

The atomic mass of lithium is a weighted average of its isotopes. Using the equation: (6.015121 * x) + (7.016003 * (1-x)) = 6.9409, solving for x gives the percent abundance of lithium-6 as approximately 7.503%.

Lithium Forms Compounds Which Are Used in Dry Cells and Storage