A student mixes 450 mL of water and 116 mL of 7.90 x 10-5 M greenfood dye solution. What is the concentration of this new dilute solution of green food dye?

Answer 1

7.90E-5 x [116/(116+450)] = ?
Note: This assumes that the volumes are additive; i.e., that 116 mL + 450 mL really is 566 mL. Some solutions are not additive.

Answer 2

the volume has increased by a factor of (450+116)/116 = 4.879

so, the concentration has decreased by that same factor.

So, that makes it 7.90/4.879 * 10^-5 = 1.62*10^-5 M