Question

Wt. of $50$ atoms of an element is $3000amu$. Calculate no. atoms in $240gm$ of element.

Answer 1

Given, Mass of $50$ atoms=$3000amu$

$\Rightarrow$ Mass of $1$ atom=$\frac{3000amu\times 1atom}{50atom}$

$=60amu$

$\Rightarrow 1atom=60amu$

Mass of $1$ mole of atoms=$60gms$

Now, given $240gm$ of element

No. of moles of atoms in $240gm$ of element is

$\frac{240g\times 1mole}{60g}=4$ moles

Now, We know $1$ mole of atoms has $6.023\times {10}^{23}$ atoms

$\Rightarrow 4$ mole of atoms have

$\frac{4mole\times 6.023\times {10}^{23}atoms}{1mole}$

$=24.092\times {10}^{23}$ atoms

$\therefore 240gm$ element has $24.092\times {10}^{23}$ atoms