On May 6, 1937, the airship (blimp) Hindenburg exploded in midair just seconds before completing its transatlantic voyage. Onboard the blimp had been 210,000 cubic meters of hydrogen gas. Since that time, airships have used helium gas rather than hydrogen gas to keep them aloft. Explain why in terms of valence electrons. PLEASE HELP WILL GIVE BRAINLIEST

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

How can carbon move from "land" to bodies of water? describe the way human impact has lead to increased levels of co2 in the atmosphere.

One way in which the useful metal copper is produced is by dissolving the mineral azurite, which contains copper(ii) carbonate, in concentrated sulfuric acid. the sulfuric acid reacts with the copper(ii) carbonate to produce a blue solution of copper(ii) sulfate. scrap iron is then added to this solution, and pure copper metal precipitates out because of the following chemical reaction: (s) (aq) (s) (aq) suppose an industrial quality-control chemist analyzes a sample from a copper processing plant in the following way. he adds powdered iron to a copper(ii) sulfate sample from the plant until no more copper will precipitate. he then washes, dries, and weighs the precipitate, and finds that it has a mass of .