[kjc]

Hello...trying to get into the swing of chemistry after several years of a break.  If someone could post the steps involved in solving the following problem, it would be appreciated.

Problem: Making a buffered acetate solution for lab, add the following: 50 ml of 2M acetic acid, 50ml of 1M sodium acetate, 50ml of 3M NaCl and 850ml dH20.  What is the final concentrations of each component?

My intial thought was to add all the volumes (totaling 1000ml = 1L).  Then for each component use the following equation...

C2 = (C1 * V1) / V2

V2 is final volume (1L)
C1 is the initial component concentration
V1 is the initial volume of the component
C2 solving for the ending component concentration

So given the above, the answers would be

Acetic Acid = 0.1M
Sodium Acetate = 0.05M
NaCl = 0.15M

Is this logic right or am I down the wrong path?  Can someone confirm/correct.


Thanks!!

[darkSun]

The way you found final concentrations is correct. But when it says each component, they probably mean the concentrations of the dissolved substances. NaCl and NaCH3COO would dissociate completely, so the concentration of Na+ would be the concentration of those two compounds added together.

But the acetate ion is more complicated. Acetic acid is a weak acid, so I think you would have to know its acid ionization constant (KA) and do an equilibrium problem considering the common ion effect to find the concentrations of acetate and H+.