An analytical chemist is titrating 220.3 mL of a 0.3600 M solution of diethylamine ((C2H5)2NH) with a 0.2600 M solution of HNO3. The pKb of diethylamine is 2.89. Calculate the pH of the base solution after the chemist has added 125.1 mL of the HNO3 solution to it. Note for advanced students: you may assume the final volume equals the initial volume of the solution plus the volume of HNO3 solution added. Round your answer to 2 decimal places.

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.

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?

Which part of the mantle is similar to the crust ? (science)