Question

In an experiment, 16 g of oxygen gas is produced. The total number of molecules present in it is __________.

• A. $6.022\times {10}^{23}$
• B. $9.033\times {10}^{23}$
• C. $2.044\times {10}^{23}$
• D. $3.011\times {10}^{23}$

Answer 1

The correct option is D $3.011\times {10}^{23}$

Given:
Mass of oxygen atom= 16 u
Gram molecular mass of $O_2$ = $2\times 16$ = 32 g

Number of moles of $O_2$ = $\frac{Givenmassingrams}{Grammolecularmass}$= $\frac{16}{32}$ = 0.5 moles

Since, number of molecules in 1 mol of a substance = $6.022\times {10}^{23}$
So, number of molecules in 0.5 mol of $O_2$
= $6.022\times {10}^{23}\times 0.5$
= $3.011\times {10}^{23}$