Using the pH=-log[ hydrogen ions], assuming the pH of water is 7 then using the concept that kw=[ OH] [H+], then the [H+]= 10 power minus 7,since kw=10 to the power minus 14
Through the vibration of particles in a medium.
First you need to know Avogadro's number which is 6.02 times 10^23 molecules in 1 mole of a substance. So now just divide your number by Avagadro's number to get the number of moles.
5. is b
but im not sure about 4
hope this helps
