Chemistry

Please help me break this problem down.. Thanks lot.

Light with a wavelength of 425 nm fell on a potassium surface, and electrons were ejected at a speed of 4.88 X 10^5 m/s. What energy was expended in removing an electron from the metal? Express the answer in joules (per electron) and in kilojoules per mole ( of electrons).

  1. 👍
  2. 👎
  3. 👁
  1. energy of the photon = hc/lambda.
    You know h,c, and lambda. Be sure to change lambda to meters.
    KE of the ejected electron
    = 1/2 mv2. Remember to use kg for mass of electron.
    Energy expended is the difference of the two. This will be per electron ejected and it will be in joules. Multiply that by 6.02 x 10^23 to change to per mol of electrons.

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    An electron is excited from the n=1 ground state to the n=3 state in a hydrogen atom. Which of the following statements are true? Correct the false statements to make them true. A. It takes more energy to ionize (completely

  2. Chemistry

    According to the quantum-mechanical model for the hydrogen atom, which of the following transitions would produce light with longer wavelength: 3p to 2s or 4p to 2s? A) The 3p to 2s transition would produce light with longer

  3. Chemistry

    Calculate the energy in joules of microwave radiation of wavelength 12.7 centimeters. (E = hν, h = 6.63 × 10-34 J.sec; speed of light = wavelength × ν, speed of light = 3.0 × 108 meters/sec.)

  4. physics

    In a double-slit experiment, it is found that blue light of wavelength 460 nm gives a second-order maximum at a certain location on the screen. What wavelength of visible light would have a minimum at the same location?

  1. Physics

    Rank in order the following according to their speeds, from fastest (1) to slowest (5): (i) 425-nm-wavelength light through a pane of glass, (ii) 500-nm-wavelength light through air, (iii) 540-nm-wavelength light through water,

  2. Science

    Which of the following correctly describes a radio wave? long wavelength and high frequency long wavelength and low frequency short wavelength and low frequency short wavelength and high frequency 3. When the energy of a light

  3. science

    When you go out into the sun, the UV light can give you a tan. UV light has a frequency of 7.89 x 1014 Hz. What is the wavelength of UV light? Please use 3 x 108 m/s for the speed of light (c). You will need to upload a file to

  4. Physics

    A monochromatic light source used in a diffraction experiment has a wavelength of 4.60 x 10- 7 m. (a) What is the frequency of this light? When you input large numbers such as those in this problem, then input the numbers with

  1. chem

    What is the longest wavelength of light that will provide photons of sufficient energy to break the pi bond and cause the isomerization? Energy required to break pi bond is 4.42*10^-19. wavelenght=c/f but how do i figure out what

  2. college chemistry

    CH4 + 2 Cl2--> CH2Cl2 + 2HCl Cl-Cl bond energy: 242 kj/mole 1. Calculate the amount of energy (Joules) needed to break a single Cl-Cl bond. 2. Calculate the longest wavelength of light (meters)that can supply the energy per photon

  3. Physics

    A helium-neon laser emits light of wavelength 633 nanometers(nm). Light from an argon laser has a wavelength of 515 nm. Which laser emits the higher-frequency light?

  4. physics

    light is an electromagnetic wave and travels at a speed of 3.00 x 108 m/s. the human eye is most sensitive to yellow-green light which has a wavelength of 5.45 x 10-7 m. what is the frequency of this light?

You can view more similar questions or ask a new question.