Question

Find the number of moles of $HN{O}_3$ molecules in a sample containing ${10}^6$ molecules of $HN{O}_3$.

• A. $2.66\times {10}^{-18}$ moles
• B. $2.66\times {10}^{-20}$ moles
• C. $1.66\times {10}^{-20}$ moles
• D. $1.66\times {10}^{-18}$ moles

Answer 1

The correct option is D $1.66\times {10}^{-18}$ moles

We know,
$6.022\times {10}^{23}$ molecules of $HN{O}_3=1$ mole of $HN{O}_3$

So, ${10}^6$ molecules of $HN{O}_3=\frac{{10}^6}{6.022\times {10}^{23}}$ moles
$=1.66\times {10}^{-18}$ moles of $HN{O}_3$