What is the mass of "0.1 mols" of electrons in "amu"?

1 Answer
Truong-Son N.
Aug 17, 2017

Well, one electron has a rest mass of approximately:

m_e = 9.109 xx 10^(-31) "kg"

So for 0.1 mols of electrons...

=> 0.1 cancel"mols" xx (N_A " things")/(cancel"1 mol") xx m_e

= 0.1N_Am_e,

where N_A = 6.0221413 xx 10^(23) "mol"^(-1) is Avogadro's number.

So, the molar mass in "g/mol" would be:

m_("0.1 mol" xx e) = 0.1 cdot 6.0221413 xx 10^(23) "mol"^(-1) cdot 9.109 xx 10^(-31) "kg"

= 5.486 xx 10^(-8) "kg/mol" = 5.486 xx 10^(-5) "g/mol"

Recall that "1 amu" is numerically equal to "1 g/mol". So,

m_("0.1 mols e"^(-)) = color(blue)(5.486 xx 10^(-5) "amu")

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