Question

Calculate mass of 3.01 × 10²⁴ atoms of an element having atomic mass 21.13.

Options

• 118.5 g mol^-1

• 105.65 g mol^-1

• 84.54 g mol^-1

• 42.27 g mol^-1

Answer 1

105.65 g mol^-1 

Explanation:

Since, 1 mol of an element = 6.022 × 10²³ atoms

`therefore 3.01 xx 10^24 "atoms" = (3.01 xx 10^24)/(6.022 xx 10^23) = 4.998`mol ≈ 5 mol

No. of. moles = `"Mass"/"atomis mass"`

∴ Mass = 5 × 21.13 = 105.65 g mol^-1