NEETChemistrySome Basic Concepts of Chemistry
The mass of a single atom of an unknown metal X is 3.82 10⁻²³ g . If Avogadro's number is 6.022 10²³ mol ⁻¹ , what is the molar mass of element X?
Options
- A23 g mol ⁻¹
- B2.3 g mol ⁻¹
- C3.82 g mol ⁻¹
- D6.34 10⁻⁴⁷ g mol ⁻¹
Correct answer
A. 23 g mol ⁻¹
Step-by-step solution
Molar mass is defined as the mass of one mole of atoms of the element. Mass of one atom of X = 3.82 10⁻²³ g Number of atoms in one mole = N_ A = 6.022 10²³ atoms mol ⁻¹ Molar mass = Mass of one atom N_ A Molar mass = (3.82 10⁻²³ g ) (6.022 10²³ mol ⁻¹) Molar mass = 23.004 g mol ⁻¹ 23 g mol ⁻¹ Dividing the mass by N_ A instead of multiplying leads to the incorrect extremely small value, while miscalculating the powers of 10 leads to 2.3 g mol ⁻¹ . Answer: 23 g mol ⁻¹