I really don't know how to approach this problem and I really need help.
Using the average molarity of your initial acetic acid solutions, the initial volumes, and the volume of NaOH added to reach the equivalence point, calculate the [C2H3O2-] concentration at the equivalence point.
# of Trials Initial V(HC2H3O2) Vol(NaOH) pH(equiv. Pt.) [OH-] C2H3O2-](eq. Pt.)
Trial 1: 31.1 21.8 7.27 1.86E-007
Trial 2: 30.1 21.7 7.10 1.26E-007
Trial 3: 29.9 24.7 7.13 1.35E-007
I have tried to make sense of this post and can't. It isn't your fault; the problem is that the board doesn't recognize spaces over one(1). You also run into problems if the amount of material covers more than one line. I suggest you do this vertically instead of horizontally. This is really a simpler problem and I can help if we can get the data straight.
Example:
Trial 1
volume acetic acid =
volume NaOH =
etc.
I am a little confused by the following:
initial volume HC2H3O2. Is that what you started with?
How much of this is your calculation versus experimental observation?
I don't get the 1.86E-007, especially the 007 part.
To calculate the [C2H3O2-] concentration at the equivalence point, you need to use the stoichiometry of the balanced chemical equation for the reaction between acetic acid (HC2H3O2) and sodium hydroxide (NaOH).
The balanced chemical equation for the reaction is:
HC2H3O2 + NaOH -> NaC2H3O2 + H2O
From the equation, you can see that the ratio of moles of HC2H3O2 to moles of NaC2H3O2 is 1:1.
To determine the moles of NaOH used at the equivalence point (moles of NaOH(eq. Pt.)), you can use the volume of NaOH added to reach the equivalence point and the concentration of NaOH:
moles of NaOH(eq. Pt.) = concentration of NaOH * volume of NaOH(eq. Pt.)
Once you have the moles of NaOH(eq. Pt.), you can use the stoichiometry of the reaction to determine the moles of HC2H3O2 at the equivalence point. Since the ratio of moles of HC2H3O2 to moles of NaOH is 1:1, the moles of HC2H3O2 at the equivalence point would be equal to the moles of NaOH(eq. Pt.).
Next, you need to calculate the total moles of HC2H3O2 at the start of the reaction. This can be done by multiplying the average molarity of the initial acetic acid solutions by the initial volume of HC2H3O2:
moles of HC2H3O2 = average molarity of HC2H3O2 * initial volume of HC2H3O2
Finally, to calculate the [C2H3O2-] concentration at the equivalence point ([C2H3O2-](eq. Pt.)), you can divide the moles of HC2H3O2 at the equivalence point by the total volume at the equivalence point (sum of the initial volume and the volume of NaOH(eq. Pt.)):
[C2H3O2-](eq. Pt.) = moles of HC2H3O2(eq. Pt.) / total volume(eq. Pt.)
You can now plug in the given values from the trials to calculate the [C2H3O2-] concentration at the equivalence point for each trial.