Chemical reactions produce new substances with different properties than the substances that reacted. Sometimes , the evidence for these new substances is easy to see .Other times, it is quite so obvious. Which of the following can be a clue that a chemical reaction has taken place ?

Aaspirin has a density of 1.40 g/cm^3 what is the volume in cubic centimeters of a tablet weighing 320 mg?

Which of the following true? a_volcanoes and earthquakes often near the plate boundaries. b_volcanoes occur whereve there are tall mountains. c_earthquakes cause volcanoes in the same location to erupt violently d_volcanoes and earthquakes occur only where plates are colliding with each other

For the following dehydrohalogenation (e2) reaction, draw the zaitsev product(s) resulting from elimination involving c3–c4 (i.e., the carbon atoms depicted with stereobonds). show the product stereochemistry clearly. if there is more than one organic product, both products may be drawn in the same box. ignore elimination involving c3 or c4 and any carbon atom other than c4 or c3.