Consider a sample of polyethylene containing 2000 chains with molecular weights ranging from 0 to 4000 g/mol; 4000 chains with molecular weights ranging from 4000 to 8000 g/mol; 3000 chains with molecular weights ranging from 8000 to 12000 g/mol; and 1500 chains with molecular weights ranging from 12000 to 16000 g/mol. Calculate the following: a. the weight average molecular weight.
b. the number average molecular weight
c. the polydispersity
d. the degree of polymerization

What is the chemical formula for a compound between li and br? libr li2br libr2 libr3

Give 2 characteristics of low mass stars

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