Why using a temperature probe is preferable to using a conventional mercury thermometers

An aqueous solution of calcium hydroxide is standardized by titration with a 0.120 m solution of hydrobromic acid. if 16.5 ml of base are required to neutralize 27.5 ml of the acid, what is the molarity of the calcium hydroxide solution?

One does not belong why? ice, gold ,wood ,diamond and table salt

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?