Question

How much positive charge is in 0.7 kg of lithium? with each atom having 3 protons and 3 electrons. The elemental charge is 1.602 × 10−19 C and Avogadro’s number is 6.023 × 1023 . Answer in units of C.

Answer 1

Step-by-step explanation:

As a neutral lithium atom contains 3 protons and its elemental charge is given as
`1.602 * 10^(-19) C`. Hence, we will calculate its number of moles as follows.

Moles =
`\frac{mass}{\text{molar mass}}`

=
`(0.7 * 1000 g)/(7 g/mol)`

= 100 mol

According to mole concept, there are
`6.023 * 10^(23)` atoms present in 1 mole. So, in 100 mol we will calculate the number of atoms as follows.

No. of atoms =
`100 * 6.023 * 10^(23)`

=
`6.023 * 10^(25)` atoms

Since, it is given that charge on 1 atom is as follows.

`3 * 1.602 * 10^(-19)C`

=
`4.806 * 10^(-19)C`

Therefore, charge present on
`6.023 * 10^(25)` atoms will be calculated as follows.

`6.023 * 10^(25) atoms * 4.806 * 10^(-19) C`

`28.95 * 10^(6)C`

Thus, we can conclude that a positive charge of
`28.95 * 10^(6)C` is in 0.7 kg of lithium.