The diagram shows the structure of the compound 1,3-butadiene, CH 2 =CH-CH=CH 2 How many molecules of hydrogen are needed to saturate one molecule of 1, 3 - bu butadiene ? A 1 B2 C 3 D4

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?