Question

How many oxygen atoms are there in $0.5$ mole of $KHS{O}_4$ ?

• A. $1.2\times {10}^{23}$
• B. $2.4\times {10}^{23}$
• C. $3.0\times {10}^{23}$
• D. $1.2\times {10}^{24}$
• E. $2.4\times {10}^{24}$

Answer 1

The correct option is D $1.2\times {10}^{24}$

1 mole of $KHS{O}_4$ contains 4 moles of oxygen atoms.
0.5 mole of $KHS{O}_4$ contains $0.5\times 4=2$ moles of oxygen atoms.
Number of oxygen atoms is obtained by multiplying number of moles of oxygen atoms with Avogadro number which is $6.023\times {10}^{23}$. The number of oxygen atoms $=2\times 6.023\times {10}^{23}=1.2\times {10}^{24}$.