Question

How many water molecular are present in one mL of water (d=1 gm/ml) ?

• A. $5.55\times {10}^{21}$
• B. $6.023\times {10}^{23}$
• C. $3.346\times {10}^{22}$
• D. $6.023\times {10}^{22}$

Answer 1

The correct option is C $3.346\times {10}^{22}$

We know that molar mass of $H_{2}O$ is $18g/mol$.

mass of water$=1ml=1g$

Therefore, number of moles of $H_{2}O=\frac{1g}{18g/mol}=\frac{1}{18}$

Number of molecules of $H_{2}O$=number of moles$\times 6.022{10}^{23}$

Number of molecules of $H_{2}O=\frac{1}{18}\times 6.022\times {10}^{23}=3.346\times {10}^{22}$