Question #72d3b

1 Answer
Stefan V.
Jun 9, 2017

#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")))#

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