Question

Suppose your unknown brass sample consists of a piece of hardware, such as a screw, and your lab is tasked with determining the copper content of the sample. One screw is not large enough to give a sufficiently concentrated solution of copper(II) ion when dissolved and diluted to 250 mL. Which of the following solutions would you choose to solve the problem?

a) dissolve two pieces

b) dissolve one piece

Explain.

Answer 1

a)

Use only one piece

Since we can asume all the material was produced with the SAME specification of material

We will most likely take the piece which will allow us to calcualte the concentration of Copper ion.

Once we know concentration , we can relate to mass content

that is:

1) identify concentration o fCu+2

2) relate to mass via molar mass

3) relate to mass sample, this is w/w% composition calculation

4) all screws will have this composition, that acocounts for the screw preivously discussed