How many atoms of 6Li are there in 12.8 g of 6Li?

Question

How many atoms of ⁶Li are there in 12.8 g of ⁶Li?

Answer 1

The steps to solving this problem are:

1). find the moles of Li by using the mass of Li and the atomic mass of Li

2). find the number of atoms of Li by using the moles of Li and Avogadro's number

The atomic mass of ⁶Li is 6.94 g / mole.

First, we will determine the number of moles of Li present in 12.8 g:

12.8 g Li x 1 mole Li / 6.94 g = 1.84 moles Li

Next, we can determine the number of Li atoms present in 1.84 moles of Li by using Avogadro's number:

1.84 moles L x 6.02x10²³ atoms / mole = 1.11x10²⁴ atoms of Li (to 3 significant figures)