Question

The difference in the mass of 100 each mole of sodium atoms and sodium ions is 5.48002 g. Calculate the mass of an electron from the above data.

• A. $9.1\times {10}^{-28}kg$
• B. $9.1\times {10}^{-31}kg$
• C. $5.4002\times 6.022\times {10}^{-31}kg$
• D. $5.4002\times 6.022\times {10}^{-28}kg$

Answer 1

The correct option is B $9.1\times {10}^{-31}kg$

$Na\to N{a}^{+}+e^{-}$

A sodium atom and ion, differ by one electron.

For $100$ moles each of sodium atoms and ions there would be a difference of $100$ moles of electrons.
Mass of $100$ moles of electrons= $5.48002g$

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

Mass of one electron $=\frac{5.48002}{100\times 6.022\times {10}^{23}}=9.1\times {10}^{-28}g$ $=9.1\times {10}^{-31}kg$