3. find the mass of 4.77 x 1022 atoms of scandium
(sc).

Mass = 3.6 g

Explanation:

Given data:

Number of atoms of scandium = 4.77×10²² atoms

Mass of arsenic = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022× 10²³ is called Avogadro number.

one mole =  6.02×10²³ atoms

one mole × 4.77×10²² atoms / 6.02×10²³ atoms

0.08 mol

Mass of scandium

Mass = number of moles × molar mass

Mass = 0.08 mol ×  45 g/mol

Mass = 3.6 g