Brass is made up of copper (density = 8.96 g/cm3) and zinc (density = 7.13 g/cm3). If the density of brass is 8.36 g/cm3 what is the percentage of copper and zinc?

the dissolution of polymer can be thermodynamically described in 2 steps.

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.

the answer is 0.42 is that is an option. this question provides no info