How to calculate the kinetic energy, energy and frequency? [ENDORSED]

[Chem_Mod]

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1.

Answer the following three questions.
A. What is the kinetic energy of the ejected electron?
B. How much energy is required to remove an electron from one sodium atom?
C. What is the frequency of the incident light on the sodium metal surface? If you can, could you give me a step by step explanation on how to solve this?

[Chem_Mod]

The steps to solve the problem are:
1. Use Ek = 1/2 mv^2 2.

2. Divide the total energy (work function) by Avogadro's number.

3. Use: kinetic energy of e- = energy of incoming photon – work function ****In addition to covering this in class, the course reader has detailed examples as does the textbook.

[derek1d]

Won't the mass of the electron need to be given in order to solve A) of this problem?

[diegomartinez1F]

Mass of electron is given:

Me= 9.10938 x 10^-31 kg

[Jacinda Wollenweber 1D]

The steps to solve the problem are:
1. Use Ek = 1/2 mv^2 2.

2. Divide the total energy (work function) by Avogadro's number.

3. Use: kinetic energy of e- = energy of incoming photon – work function ****In addition to covering this in class, the course reader has detailed examples as does the textbook.

Why do we have to divide the work function by Avogrado's number? I thought the energy was given simply by adding the kinetic energy and threshold energy together.

[Sarah_Wilen]

This is because the work function's energy is given in kJ/mol. You need to solve for the energy of a single unit. That was very poorly explained, sorry. Refer to this other answer:
viewtopic.php?f=14&t=21193

[Kevin Morden 1E]

Mass of electron is given:

Me= 9.10938 x 10^-31 kg

Is the mass of an electron always going to be the same?

[Chem_Mod]

Yes, the mass of an electron is always going to be the same.

[Sohini Halder 1G]

As Dr. Lavelle said in lecture, it always helps to write out the equation in words first.
For example:
Energy of incoming photon = Workfunction of metal (or energy needed to remove electron) + Kinetic energy of the electron emitted
After this, you can rearrange whatever way you need to for the problem.

[Kevin Hernandez 3A]

The steps to solve the problem are:
1. Use Ek = 1/2 mv^2 2.

2. Divide the total energy (work function) by Avogadro's number.

3. Use: kinetic energy of e- = energy of incoming photon – work function ****In addition to covering this in class, the course reader has detailed examples as does the textbook.

For Part c, would you subtract the work function of the sodium metal or subtract the work function of the one sodium atom?

[gabbym]

This was so helpful, thank you!

[Ashley P 4I]

At last I finally understood what this problem was asking, thank you so much!

[Liza Hayrapetyan-3K]

Thank you so much! This was extremely helpful.

[Andrew Bennecke]

Thank you, I was genuinely confused about this topic as well!

[Yiting_Gong_4L]

Thank you for this explanation! This was very helpful.