Electronic Instrumentation
posted by Kevin .
Calculate the force in Newtons that exists between a positive charge of 2C and a negative charge of 5.2 X 10^19 electrons separated by a distance of 25 cm.

f=kqq/r^2
I will be happy to critique your work. 
I'm having trouble finding Q2.
5.2 x 10^19 x 6.2 x 10 ^18? 
The "Q2" charge, of the 5.2*10^19 electrons, is
5.2*10^19*1.6*10^19 C/electron
= 8.32 Coulombs
Your number of 6.2*10^18 is the number of electrons per Coulomb. If you had divided by that number instead of multiplying, you would have gotten the right answer.