List the four different ways that molecules can be excited to ...

[darbym82]

List the four different ways that molecules can be excited to produce spectra.
 
  What will be an ideal response?

Question 2

Describe how the motion of Uranus led to the discovery of Neptune.
 
  What will be an ideal response?

[underwood14]

Answer to Question 1

In addition to becoming excited through collisions or absorbing radiation, molecules can also rotate and vibrate.

Answer to Question 2

Uranus at first was moving faster than predicted, then after 1822 mysteriously slowed down, as it had passed Neptune and was now pulled back by Neptune's gravity. Adams and Leverrier used this perturbation to predict the position of Neptune, which Galle used to telescopically locate its blue disk.

[darbym82]

Excellent

[shewald78]

Gracias!