CHM 1045
Dr. Michael Blaber

Name_________________________

SS #__________________________

Homework # 5

(Due in Recitation Tues Oct 12)

 

  1. An electromagnetic radiation has a frequency of 4.0 x 1014 s-1. What is the wavelength of this radiation and what color (if any) would it be perceived as? (1 point)

    2. n * l = c

    l = c / n = (3.0 x 108 m/s) / (4.0 x 1014 s-1) = 750 x 10-9 m (or 750 nm)

    This is right at the edge of the visible spectrum. It would be red in color.

  2. The following diagram shows electromagnetic radiation with a wavelength of 600 nm (visible as an orange light). Beneath this, draw a waveform for violet colored light at the edge of the visible spectrum, which has an intensity 50% greater than the orange light (1 point)

  3. An ultraviolet military laser has a wavelength of 350 nm. It is able to deposit 1.8 x 1026 quanta of energy upon a target with a single blast. How many Joules of energy is the target potentially absorbing? (2 points)

    4. n = c / l = (3.0 x 108 m/s) / (350 * 10-9 m) = 8.57 x 1014 s-1

    E = h * n = (6.63 x 10-34 J s) * (8.57 x 1014 s-1) = 5.68 x 10-19 J per quanta

    1.8 x 1026 quanta * (5.68 x 10-19 J /quanta) = 1.02 x 108 J

  4. An electron transitions from the n = 3 to the n = 2 quantum state of the hydrogen atom. What is the wavelength of the associated photon? (1 points) Is the photon absorbed or emitted for the associated electron transition? (1 point). In what area of the electromagnetic spectrum is this located and is it visible light? (1 point)

    5. n = (RH/h)*(1/ni2 - 1/nf2) = (2.18 x 10-18 J / 6.63 x 10-34 J s)*(1/9 - 1/4) = -4.57 x 1014 s-1

    l = c / n = (3.0 x 108 m/s) / (4.57 x 1014 s-1) = 6.57 x 10-7 m or 657 nm

    n = -4.57 x 1014 s-1 negative value indicates light is emitted (when electron falls down to lower energy level)

    l = 657 nm , so this is in the visible of the spectrum (i.e. reddish orange light)

  5. Consider the wave behavior of matter: an electron is accelerated to 1/10th the speed of light. What is the electron's characteristic wavelength? (1 point)

    6. l = h/(mv) = (6.63x10-34 J s)/((9.11x10-31 kg)*(0.3x108 m/s)) = 2.43x10-11 J kg-1 m-1 s2

    = 2.43x10-11 J kg-1 m-1 s2 * (1 kg m2 s-2 / J) = 2.43 x 10-11 m or 0.0243 nm

  6. What is the designation for the electron subshell with principle quantum number = 3 and azimuthal quantum number = 1 ? (1 point)

    7. n = 3, l = 1

    3p

  7. How many orbitals are there in the subshell with a principle quantum number of 3, and an azimuthal quantum number of 1 (1 point)

n = 3

l = 1

3p, which has 3