Question

Calculate the number of moles in 1 L water, also calculate the number of water molecules in 1 L water.

Answer 1

Since density of water$=1g/c{m}^3=1000g/L$, hence

Weight of $H_{2}O=1000g$

Number of moles$=\frac{1000}{18}=55.59$

Since 1 mole of $H_{2}O$ contains $6.022\times {10}^{23}$ molecules of water, hence

55.56 moles of water will contain $55.59\times 6.022\times {10}^{23}=3.345\times {10}^{25}$ molecules of water