Question

Calculate the number of electrons present in 60 g of water.

Answer 1

The gram molecular mass of water is 18 g.
Given mass of water = 60 g
Number of gram molecules = $\frac{\text{Mass of water}}{\text{Gram molecular mass of water}}$ ...(i)

After putting the values of given mass of water and gram molecular mass of water in equation (i) we have:

Number of gram molecules = $\frac{60}{18}$
Number of gram molecules = 3.33

1 gram molecule of water contains $6.022\times {10}^{23}$ molecules of water

The number of water molecules present in 60 gram (3.33 gram molecules) of water = $3.33\times 6.022\times {10}^{23}$
= $20.05\times {10}^{23}$

Number of electrons present in one molecule of $H_{2}O$ is 10

Therefore, number of electrons = $10\times 20.05\times {10}^{23}$

Number of electrons present in 60 g of water is $2\times {10}^{25}$