Ahelium balloon contains 0.48 g of helium. given the molecular weight of helium is 4.0g/mol, how many moles of helium does it contain?

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 co(g) are there in 74.5 ml of the gas at 0.933 atm and 30o c?

What best discribes the relationship between wavelength and frequency in a electromagnetic wave