Question

Question #72d3b

Answer 1

`5 * 10^(-4)` `"g"`

Explanation:

In order to figure out the mass of `1` mole of electrons, you need to know the mass of a single electron.

You will find it listed as

`m_ ("e"^(-)) ~~ 9.10938 * 10^(-28)` `"g"`

https://en.wikipedia.org/wiki/Electron_rest_mass

Now, `1` mole of electrons is defined as a very, very large collection that consists of `6.022 * 10^(23)` electrons. This value, which represents the definition of a mole, is called Avogadro's constant.

So, you know the mass of single electron and the total number of electrons needed to make `1` mole, so plug in your values and do the calculations

`6.022 * 10^(23) color(red)(cancel(color(black)("e"^(-)))) * (9.109383 * 10^(-28)color(white)(.)"g")/(1color(red)(cancel(color(black)("e"^(-))))) = 5.486 * 10^(-4)` `"g"`

Rounded to one significant figure, the answer will be

`color(darkgreen)(ul(color(black)("mass of 1 mole e"^(-) = 5 * 10^(-4)color(white)(.)"g")))`