Question

Calculate the radius of a water molecule assuming to be spherical (density $=1gm{L}^{-1}$ ).

• A. $1.925\times {10}^{-8}cm$
• B. $1.925\times {10}^{-9}cm$
• C. $1.925\times {10}^{-10}cm$
• D. $1.925\times {10}^{-11}cm$

Answer 1

Answer: (A)

Mass of one molecule $=\frac{18}{6.02\times {10}^{23}}g$ Volume of one molecule $=\frac{18g}{6.02\times {10}^{23}\times 1}$ $=3.0\times {10}^{-23}$ $\frac{4}{3}\pi r^3=3.0\times {10}^{-23}$ $r^3=\frac{3\times 3.0\times {10}^{-23}\times 7}{4\times 22}$ $r=1.925\times {10}^{-8}cm$