Question

Estimate the radius of water molecule .Given molecular weight of water=18g/mole and Avogadro's number =6×10^23 molecules/mole,density of water=1000kg\m^3 ​

Answer 1

Radius of water molecule is 0.1925 nm.

Given-

• Molecular weight of water = 18 gram/ mol
• Avagadro's number = 6.023 × 10²³
• Density of water = 1000 kg/m³

We know that density is mass per unit volume.

Volume of 1 mole of water = Mass/Density = 18/1 g/cm³ = 18 cm³ = 18 × 10⁻⁶ m³

1 mole of water contains 6.023 × 10²³ molecules of water

Volume of 1 molecule of water = 18 × 10⁻⁶ / 6.023 × 10²³ = 0.2988 × 10⁻²⁸ m³

We know that volume of sphere is = 4/3 πr³ where r is the radius.

So,

4/3 πr³ = 0.2988 × 10⁻²⁸ m³

r = 0.1925 × 10⁻⁹ m = 0.1925 nm

Answer 2

Hope this answer help you