In the laboratory, a student adds 57.6 mL of water to 10.9 mL of a 0.755 M perchloric acid solution. What is the concentration of the diluted solution ?

Answer 1

.755 M * 10.9 / (10.9 + 57.6)

Answer 2

I know I'm being picky BUT that answer, while true in most instances in reality, technically it is true ONLY when the volumes are additive. In some cases they are not.