Answer:
3× 10²³ atoms
Step-by-step explanation:
Given data:
Mass of B = 5.40 g
Number of atoms = ?
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.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For 5.40 g of B:
Number of moles = mass/ molar mass
Number of moles = 5.40 g/ 10.811 g/mol
Number of moles = 0.5 mol
one mole = 6.022 × 10²³ atoms
0.5 × 6.022 × 10²³ atoms
3× 10²³ atoms