Write down a general expression for the energy of the photon required to excite a hydrogen-like atom with nuclear charge Z from the ground state to the first excited state. Calculate the energies and wavelengths of the photons needed to excite the ground state species H, He+ and Li2+. In what region of the electromagnetic spectrum are the photons?

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

answerleaving cheese out to get moldy;