5 Steps to a 5 AP Chemistry

b. This equation requires the de Broglie relationship (also given in the AP exam booklet).

Do not mistake a vfor a n. You will also need to know J =kg m^2 /s^2.

This answer is worth 1 point.

c. This can be done as a one-step or a two-step problem. The AP test booklet gives you

the equations to solve this directly as a two-step problem. This method will be followed

here. The two equations may be combined to produce an equation that will allow you

to do the problem in one step.

Using c=ln:

Using ΔE=hn:

ΔE=(6.63 × 10 −^34 Js)(5.4 × 1014 s−^1 )(1 kJ/1000 J)(6.022 × 1023 /mol)

=2.2 × 102 kJ/mol

Give yourself 1 point for each of these answers. If you did the problem as a one-step

problem, give yourself 2 points if you got the final answer correct, or 1 point if you left out

any of the conversions.

The total for this question is 6 points, minus 1 point if any answer does not have the

correct number of significant figures.

 Rapid Review

• Know the regions of the electromagnetic spectrum.


• The frequency, n, is defined as the number of waves that pass a point per second.


• The wavelength, l, is the distance between two identical points on a wave.


• The energy of light is related to the frequency by E=hn.


• The product of the frequency and wavelength of light is the speed of light: c=nl


• An orbital or wave function is a quantum mechanical, mathematical description of the
  electron.


• If all electrons in an atom are in their lowest possible energy level, then the atom is said
  to be in its ground state.


• If any electrons in an atom are in a higher energy state, then the atom is said to be in an
  excited state.


• The energy of an atom is quantized, existing in only certain distinct energy states.

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⎝

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.

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Js

g

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Spectroscopy, Light, and Electrons  145