Question

For each titration you will obtain a measured value table and two graphs. The measured value table
consists of the following : volume of HCl in mL, DV, pH, DpH and derivative DpH/DV. The first
graph is a plot of pH vs mL of 0.1 M HCl added. The steepest parts of the plot indicate the two
equivalence points (indicated by the dotted lines). The second graph is a first derivative plot of
DpH/DmL vs mL of 0.1 M HCl added. The two equivalence points are determined fr

Answer 1

From lab, "Potentiometric Acid Base Titration: Analysis of an Unknown Mixture Containing Carbonate
and Bicarbonate Species (Automatic Titrator)"

Answer 2

I already figured out R3 for 3 samples, which are -0.239 mmol, -0.238 mmol and -0.239 mmol.

Answer 3

They're negative because for some awful reason my samples were extremely pure, and no extra signals were given at R2 for all of them.

Answer 4

:(y)

Answer 5

What da ell was that

Answer 6

@hwyl @abb0t @nincompoop @roast_master_says

Answer 7

I think nincompoop hates my guts.

Answer 8

it was (y) means nice shot

Answer 9

@Empty

Answer 10

i have brought u back to the land of chemistry

Answer 11

erm

Answer 12

well is it a que. or just a procedure :P

Answer 13

For each titration you will obtain a measured value table and two graphs. The measured value table
consists of the following : volume of HCl in mL, DV, pH, DpH and derivative DpH/DV. The first
graph is a plot of pH vs mL of 0.1 M HCl added. The steepest parts of the plot indicate the two
equivalence points (indicated by the dotted lines). The second graph is a first derivative plot of
DpH/DmL vs mL of 0.1 M HCl added. The two equivalence points are determined from the two
maxima and the volumes of 0.1 M added to the equivalence points are recorded. The results are
calculated according to the following formula:
R1 = Q1
R2 = Q2
Where Q is the number of mmol of titrant that has been delivered. You will have to calculate a third
result R3 which is:
R3 = Q2 – Q1
This takes into account the mmol of the original carbonate that was converted into bicarbonate after
the first equivalence point.
Use the results obtained from R1 and R3 (in millimoles) to calculate the milligrams of sodium
carbonate and sodium bicarbonate present in the original sample. Remember that you used 10 mL
aliquot in the titration out of the total sample volume of 100 mL.

Answer 14

There ya go!

Answer 15

Question specifically was "Use the results obtained from R1 and R3 (in millimoles) to calculate the milligrams of sodium carbonate and sodium bicarbonate present in the original sample.". I'm such a goof.

Answer 16

R3 for 3 samples, which are -0.239 mmol, -0.238 mmol and -0.239 mmol.