Question

State true or false.
Mass of 1 mole of electrons in $5.48 \times {10^{ - 7}}\;{\rm{kg/mol}}$
A. True
B. False

Answer 1

Hint: We know that mass of an electron is $9.109 \times {10^{ - 31}}\;{\rm{kg}}$. Now, we have to find the number of electrons in 1 mole. The multiplication of total numbers of electrons in one mole with mass of an electron gives the mass of one mole of electrons.

Complete step-by-step solution:
The mole or mol (abbreviation form) is the unit which measures the amount of substance present. A mole is the term that defines the number of carbon (C) atoms in 12 g of pure carbon. After so many years of experiment, it has been proved that a mole of anything contains $6.022 \times {10^{23}}$representative particles.
Now, we found that in one mole electrons, $6.022 \times {10^{23}}$particles present. So, multiplying the number of particles in one mole with mass of one electron will give the mass of one mole of electrons.

$\begin{align}
& {\rm{Mass}}\;{\rm{of}}\;{\text{one mole electron}} = 6.022 \times {10^{23}} \times 9.109 \times {10^{ - 31}}\;{\rm{kg}}\\
&= {\rm{54}}{\rm{.854}} \times {10^{ - 8}}\;{\rm{kg}}\\
&{\rm{= 5}}{\rm{.48}} \times {\rm{10}} \times {10^{ - 8}}\;{\rm{kg}}\\
&{\rm{ = 5}}{\rm{.48}} \times {\rm{1}}{{\rm{0}}^{ - 7}}\;{\rm{kg}}\\
\end{align}$

Hence, mass of one mole of electron is ${\rm{5}}{\rm{.48}} \times {\rm{1}}{{\rm{0}}^{ - 7}}\;{\rm{kg}}$.

So, option A is correct, that is the given statement is true.

Additional information:
An atom consists of three subatomic particles, that is, electron, proton and neutron. Electrons carry negative charge, proton carries positive charge and neutrons in neutral. Nucleus is present in the centre of the atom. The atomic number of an element represents the number of protons in the atom of the element, the number of protons and neutrons in an atom gives the mass number of the atom.

Note:
The number $6.022 \times {10^{23}}$ is a special number that denotes the number of representative particles in 1 mole of any substance. This number is named in honor of the Italian physicist Amedeo Avogadro as Avogadro’s number. So, the relation between mole and Avogadro’s number is $1\;{\rm{mol}} = 6.022 \times {10^{23}}\;{\rm{particles}}$.