Question

The total negative charge on the electrons in 1 kg of helium

Answer 1

n = m/M

= 1000/4 mol 

= 250 moles 

N = n*6,022*10^23

= 1,51*10^26 e- 

total charge: (1,51*10^26)* (1,6*10^-19)

= 2,4*10^7 C=2,4∗107C 

Answer 2

Given:

1kg of Helium.

To FInd:

Total negative charge present in it.

Solution:

Total number of electrons in 1 atom of Helium=2

Total number of moles of Helium in 1kg, $n=\frac{Given Mass(m)}{Molar Mass (M)}=\frac{1000g}{4g}=250$

Number atoms of Helium $=nN_A$     (where $N_A=6.022*10^{23}$ particles/mol)

                                          $=250*6.022*10^{23}$

                                          $=1.5*10^{26}$ atoms

So, the total number of electrons $=2*1.5*10^{26}=3*10^{26$ .

The negative charge of one electron, $e=1.6*10^{-19}C$

The negative charge of $3*10^{26$ electrons $=1.6*10^{-19}*3*10^{26}$

                                                              $=4.8*10^{7}C$

Hence, the total negative charge present in 1kg of Helium is equal to $4.8*10^{7}C$.