The mineral magnesite contains magnesium carbonate, mgco3 (molar mass= 84 g/mol), and other impurities. when a 1.26-g sample of magnesite was dissolved in hydrochloric acid, 0.22 g of co2 was generated. if the magnesite contained no carbonate other than mgco3, what was the percent mgco3 by mass in the magnesite? the reaction is as follows:
mgco3(s) + 2hcl (aq) --> mgcl2(aq) + h20(l) + co2(g)

If 34.2 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 299 kelvin and 1.21 atmospheres? 2 li (s) + 2 h2o (l) yields 2 lioh (aq) + h2 (g)

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

The variability in marine salinity between habitats does not impact the fish living there. select the best answer from the choices provided t f