In the laboratory a student combines 41.7 mL of a 0.386 M iron(III) fluoride solution with 21.3 mL of a 0.616 M iron(III) bromide solution.

Question

What is the final concentration of iron(III) cation ?

Answer 1

What is (41.7*.386+21.3*.616)/(41.7+21.3)

Now why does that work? Remember in algebra the candy mix problems?