[sweetlove]

i don't even know where to begin with this problem. this is my first week in chem. i'm gonna die.

What is the mass in grams of a brass cylinder having a length of 2.12 in. and a diameter of 0.524 in., if the composition of the brass is 67.0% copper and 33.0% zinc by mass? The density of copper is 8.92 g/cm^3, and the density of zinc is 7.14 g/cm^3. Assume that the density of the brass varies linearly with composition.

can someone explain how to do this? thanks.

[jeffrey.struss]

This is a fractional composition problem. It is actually really hard to figure out how to give you a hint without giving the answer.

The first thing I would do is get the volume of the cylinder in cm³. Then work out your total density which is actually super simple. I bet you can figure that part out on your own. From there multiply the volume by the density and there is your answer.