How do you calculate molecular weight

All cells are made of four types of acids, lipids, proteins, and carbohydrates.

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?

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.