Question

The difference in the mass of 100 moles each of sodium atoms and sodium ions is 5.48002 g. Compute the mass of an electron

Answer 1

Step 1: Given data

Mass of $100$moles of electrons = $5.48002g$

As we know sodium atoms and ions differ by one electron.

For $100$ moles of each sodium atom and ion, there would be a difference of $100$ moles of electrons.

Step 2: Formula used :

Mass = $\frac{\mathrm{given}\mathrm{mass}}{\mathrm{number}\mathrm{of}\mathrm{moles}}$

Step 3: Calculating the mass of the electron

Mass of $1$ mole of electron =$\frac{5.48002}{100}g$

Mass of one electron = $\frac{5.48002}{(100\times 6.022\times {10}^{23})}$ , where$6.022\times 10{}^{23}$ is Avogadro number

Thus calculated mass of one electron = $9.1\times {10}^{28}g$

Hence, the mass of one electron =$9.1\times {10}^{-31}$ kg.