Question

How do you calculate the initial concentration of the ions in a reaction mixture using given volumes and concentrations? Please show the calculations for:

- 2 ml of .001M Na2S2O3; want Initial [S2O3 2-] (M)

- 2 ml of .01M KI; want initial [I-] (M)

- 2 ml of .04M KBrO3 ; want inital [BrO3-] (M)

- 2 ml of .1M HCl; want initial [H+] (M)

Answer 1

just use the equation: M(1) x V(1) = M(2) x V(2) where the M's stand for Concentrations, V's stand for volume. the 1's stand for initial, 2's stand for final. remember that V(2) will be the total volume, 60ml. the M(1) will be the concentrations before the mixture is made, and M(2) is what your looking for, the final concentration of that ion. your going to have to do this 3 times, for water you cant find the M(2) because its DI (im guessing that stands for deionized) water, its only going to take part in diluting the ions further (making the M(2) lower)