Question

Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 . A fitting composed of common brass has a total volume of 114.5 .How many atoms of copper does the fitting contain?

Answer 1

8.48 WHAT?
114.5 WHAT?

Answer 2

density of 8.48 g/cm3
volume of 114.5 cm3
of brass

Answer 3

114.5 cc volume.
8.48 g/cc = density.
mass = volume x density = 114.5 cc x 8.48 g/cc = ??grams.

37% of that is Zn; therefore, (100-37 = %Cu)
?? grams x 0.63 = g Cu.
Convert that to moles (moles = grams/molar mass), then to atoms remembering that 1 mole of atoms contains 6.022 x 10^23 atoms of Cu.