A student dissolves 7.9 g of stilbene (C14H12) in 475. mL of a solvent with a density of 1.03 g/mL. The student notices that the volume of the solvent does not change when the stilbene dissolves in it. Calculate the molarity and morality of the students solution. Round both of your answers to 2 significant digits.

The zinc within a copper-plated penny dissolves in hydrochloric acid if the copper coating is filed down in several spots (so that the hydrochloric acid can reach the zinc). the reaction between the acid and the zinc 2h+(aq)+zn(s)→h2(g)+zn2+(aq) . when the zinc in a certain penny dissolves, the total volume of gas collected over water at 25 °c is 0.947 l at a total pressure of 743 mmhg . (vapor pressure of water is 23.78 mmhg at 25 °c .) what mass of hydrogen gas is collected? answer in appropriate significant figures