If a student used 1.415 grams of unknown metal, and collected 0.082 moles of H2 gas, what is the molar mass of the metal

Name the element in group 17, period 2. (periodic table)

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

If one fission reaction of a uranium-235 atom produced two neutrons, how many neutrons would be released if the chain reaction occurred three more times?