A system of 1470 particles, each of which is either an electron or a proton has a net charge of -5.456 x 10^-17 C. (a) How many electrons are in this system? (b) What is the mass of this system?

Respuesta :

Answer:

a

[tex]N_e  =  906 \  electrons[/tex]

b

[tex]M =  9.43 *10^{-25} \  kg[/tex]

Explanation:

From the question we are told that

   The total number of particles is  n =  1470 particles

    The  the total amount of charge on the particles is  [tex]Q =  - 5.456*10^{-17} \  C[/tex]

Generally this total number of particles can be mathematically represented as

      [tex]n  =  N_p + N_e[/tex]

Where  [tex]N_p \  and  \  N_e[/tex] represent the number of proton and electron respectively

=>    [tex]N_p  =  1470  -  N_e[/tex]

Also the total charge of these particles can be mathematically represented as

       [tex]Q = (N_p  - N_e ) e[/tex]

Here e is the charge on a single electron or proton with value  

The  negative sign is due to the fact the electrons are negative signed

     [tex]e =  1.60 *10^{-19} \  C[/tex]

[tex]-5.456*10^{-17} = ( 1470 -2N_e )* 1.60 *10^{-19}  [/tex]

    [tex]N_e = 906[/tex]

Thus  

      [tex]N_p  =  1470 - 906[/tex]

      [tex]N_p  =  564[/tex]

Generally the mass of the system is mathematically represented as

     [tex]M  =  N_e  * M_e  +  N_p  *  M_p[/tex]

Here  [tex]M_e  \  and  \  M_p  \  are  \  mass  \  of  \  electron \  and \  proton \  with \  values \\   M_e = 9.1 *10^{-31} \  kg \  and  \  M_p  =  1.67 *10^{-27} \  kg  \ respectively[/tex]

So

     [tex]M  =  906 *  9.1 *10^{-31}  +  564  *  1.67 *10^{-27}[/tex]

      [tex]M =  9.43 *10^{-25} \  kg[/tex]