Question

Calculate the number of atoms present in $6.4g$ of sulphur.

• A. $2.4\times {10}^{23}$ atoms
• B. $2.4\times {10}^{-23}$ atoms
• C. $1.2\times {10}^{23}$ atoms
• D. $1.2\times {10}^{-23}$ atoms

Answer 1

The correct option is C $1.2\times {10}^{23}$ atoms

Weight of $S$ $=6.4$ g
Atomic weight of $S$ $=32$ g/atom
Number of gram atoms of $S$ $=\frac{6.4g}{32g/atom}=0.2$ gram atoms.
The Avogadro's number is $6.023\times {10}^{23}$ atoms/ g atom
The number of atoms of $S$ $=0.2$ gram atoms $\times 6.023\times {10}^{23}$ atoms/ g atom
$=1.2\times {10}^{23}$ atoms

Hence, option C is correct.