Write the empirical formula for at least four ionic compounds that could be formed from the following ions:
a). po_4^3-,
b). nh_4^+,
c). fe^3+,
d). clo_3^-

Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12.0 u.

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?

Which of the following would not diffuse through the plasma membrane by means of simple diffusion? 1 oxygen 2 glucose 3 a steroid hormone 4 a lipid soluble vitamin