Question

Calculate the atomic mass of gallium, symbol Ga. Gallium has two isotopes: Ga-69 and Ga-71. The relative abundance of Ga-69 is 60.12% and its atomic mass is 68.9257 amu. The relative abundance of Ga-71 is 39.88% and its atomic mass is 70.9249 amu

Answer 1

Answer:

The atomic mass of gallium (Ga) = 69.723 g/mol

Explanation:

Given: Two isotopes of Gallium (Ga) are Gallium-69 (⁶⁹Ga) and Gallium-71 (⁷¹Ga)

For ⁶⁹Ga:

Relative abundance = 60.12% = 60.12 ÷ 100 = 0.6012; Atomic mass = 68.9257 g/mol

For ⁷¹Ga:

Relative abundance = 39.88% = 39.88 ÷ 100 = 0.3988; Atomic mass = 70.9249 g/mol

∴ The atomic mass of Ga = (Relative abundance of ⁶⁹Ga × Atomic mass of ⁶⁹Ga) + (Relative abundance of ⁷¹Ga × Atomic mass of ⁷¹Ga)

⇒ Atomic mass of Ga = (0.6012 × 68.9257 g/mol) + (0.3988 × 70.9249 g/mol) = 69.723 g/mol

Therefore, the atomic mass of gallium (Ga) = 69.723 g/mol