Answer:
Mass = 25.37 × 10⁻⁸ g
Explanation:
Given data:
Number of grams of Co = ?
Number of molecules = 2.57×10¹⁵
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
For Co:
2.57×10¹⁵ molecules × 1 mole / 6.022 × 10²³ molecules
0.43 × 10⁻⁸ moles
Mass of Co:
Mass = number of moles × molar mass
Mass = 0.43 × 10⁻⁸ mol × 59 g/mol
Mass = 25.37 × 10⁻⁸ g
