Question

The dreaded rock problem. An ICP experiment was performed to find the concentration of copper in
a rock (3.1416 g). The rock was ground up and reacted with 40 mL of concentrated nitric acid to dissolve all the
copper. The solution was diluted 1:1000 (let’s call this solution R) and gave an emission signal intensity of
46582.9 (arbitrary units). Then a 50 mL aliquot of solution R was mixed with 5 mL of a 16.4 ppm Cu solution and
diluted to 100 mL (let’s call this solution S). Solution S gave an emission signal intensity of 70159.3.
a. What is the concentration of Cu in solution R?

b. What is the mass of Cu in the rock?

Answer 1