4. Reacţiile de adiţie la alchene decurg cu scindarea legăturilor: a)  C-C b)  C-C c)  C-C şi  C-C d)  C-H 5. Clorura de vinil (CH 2 =CH-Cl) este un monomer important pentru obţinerea policlorurii de vinil din care se fabrică piele artificială. Se cere: a) scrierea ecuaţiei reacţiei chimice b) masa molară medie a polimerului dacă gradul de polimerizare n=1000 c) cantitatea de clorură de vinil necesară obţinerii a 100kg polimer dacă randamentul de reacţie este  = 80% 6. Prin arderea a 4 moli dintr-o alchenă se consumă 18 moli oxigen. Identifică alchena. Mase atomice: C-12, H-1, Cl-35,5

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.

Which of the following ocean acidification? are the most likely side effects of a ph less than 7.0 in the ocean b. more metal salts altering the ocean chemistry c. dissolution of the shells of marine organisms d. both a & b e. all of the above.

Seltzer water is created by placing water under pressure with carbon dioxide gas. which of the following statements best describe seltzer water: a. the solution will be slightly acidic b. the solution will be slightly basic. the solution will be strongly acidic. d. the solution will be strongly basic. e. the solution will be neutral