21. A chemist mixed two substances together: a blue powder with no smell and a colorless liquid with a strong smell. Their repeating groups of atoms
are shown above on the left. After they were mixed, the chemist analyzed
the results and found two substances. One ending substance had the
repeating group of atoms shown above on the right. Is the ending
substance the same substance as the blue powder? What happened to
the atoms of the starting substances when the ending substances
formed?

Island arcs island arcs are long, curved chains of oceanic islands associated with seismic activity and mountain-building processes at certain plate boundaries. they occur where oceanic tectonic plates collide. along one side of these island arcs, there is usually a long, narrow deep-sea trench. at island arcs, the denser plate is subducted and is forced into the partially molten mantle under the less dense plate. the islands are composed of the extrusive igneous rocks basalt and andesite. the basalt originates most likely from the plastic mantle. the andesite originates most likely from the melting of parts of the descending plate and sediments that had accumulated on its surface. which list identifies minerals present in andesite from the greatest percentage by volume to the least percentage by volume?