A compound with a molecular formula c8H10 produces an It spectrum with many signals including 3108,3066, 3050, 3018, and 1608 cm-1. The NMR spectrum of this compound exhibits a singlet at 2.2 ppm(I=6H) and a multiplet at 7.1 ppm (I=4H). The 14c r spectrum of this compound exhibits signals at 19.7, 125.9, 129.6, and 136.4 ppm. Draw the structure of this compound

Hot air balloons float in the air because of the difference in density between cold and hot air. in this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. to do this, use the following variables and make these assumptions: the combined weight of the pilot basket together with that of the balloon fabric and other equipment is w. the volume of the hot air inside the balloon when it is inflated is v. the absolute temperature of the hot air at the bottom of the balloon is th (where th> tc). the absolute temperature of the cold air outside the balloon is tc and its density is ďc. the balloon is open at the bottom, so that the pressure inside and outside the balloon is the same. as always, treat air as an ideal gas. use g for the magnitude of the acceleration due to gravity.

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?

Scientists have developed an explanation of a phenomenon from several verified hypotheses. the explanation has been confirmed through numerous experimental tests. which option best describes this explanation? a. scientific lawb. research questionc. hypothesisd. scientific theory