The American Dental Association recommends that an adult female should consume 3.0 mg of fluoride (F-) per day to prevent tooth decay. If the fluoride is consumed as sodium fluoride (45.24% F by mass), what amount of sodium fluoride (in milligrams) contains the recommended amount of fluoride?

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.

Why is the melting of ice a physical change ?

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.