## Kinetic Energy and Moles

$E=hv$

Dustin Shin 2I
Posts: 64
Joined: Fri Sep 28, 2018 12:26 am

### Kinetic Energy and Moles

In Test 2, one of the questions given was to find the total kinetic energy in 5 mol of ejected electrons. I used the Ek = 1/2mV^2 to find the kinetic energy and using the given numbers, my answer came to 1.82 x 10^-24 J. However this answer was wrong. I am wondering if I was supposed to multiply my final answer by 5 because I vaguely remember the textbook stating something about how answers are given in energies per mol. So was I supposed to multiply by 5 or did I do something else wrong?

Posts: 74
Joined: Fri Sep 28, 2018 12:29 am

### Re: Kinetic Energy and Moles

Remember that in the equation E=hv, E is the energy of only one photon...in this case photons are equivalent to particles so you would have to find out how many particles are in 5 mol of the substance and multiply that by the answer you got....that way you calculated the amount of energy ejected by 5 mol of photons.

Hope this helps :)