1. Tooth enamel consists mainly of hydroxyapatite (Ca5(PO4)3(OH). When tin(II)fluoride is added to toothpaste it reacts with the enamel to produce a more decay-resistant material fluoroapatite ( Ca5(PO4)3F. The by-products of this reaction are tin(II)oxide and water. What mass of hydroxyapatite can be converted to fluoroapatite by reaction with 0.115 grams of tin(II)fluoride

Island arcsisland 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? a) biotite, plagioclase feldspar, amphiboleb) biotite, amphibole, plagioclase feldsparc) plagioclase feldspar, biotite, amphiboled) plagioclase feldspar, amphibole, biotite