Question

Can someone please explain to me what tritations are and how they work?

Answer 1

If you mean titration, it is taking an unknown concentration, but known volume, of an acid or base with an indicator and adding a known concentration and volume of a base or acid until the neutralization reaction has completed as shown by the indicator changing color.

Answer 2

So how do they figure out the pH of this substance by that?

Answer 3

Of the original substance or the titrated one?

Answer 4

The original.

Answer 5

Once you know the volume of acid/base it took to take the neutralization reaction to completion, you can calculate the moles needed to titrate. Then using the balanced reaction, you can find the moles of the unknown concentration. Dividing that be the volume gives concentration.

Answer 6

Concentration of a strong acid or base is equal to the concentration of hydronium or hydroxide, respectively. Then you use pH=-log[H3O+] or pOH=-log[OH-] and pH+pOH=14.

Answer 7

Could you do an example?

Answer 8

Give me a min or two to get one ready for ya.

Answer 9

Cool.

Answer 10

Say you have 11.6 mL of 1.0M H2SO4 which has titrated 25.00 mL of an unknown concentraction of NaOH.

Answer 11

*concentration

Answer 12

I would first write the balanced reaction.
H2SO4 + 2NaOH -> 2H2O + Na2SO4

Answer 13

Then, 11.6 mL H2SO4 * (1 L/1000mL) * (1 mol H2SO4/1L) *(2 mol NaOH/1 mol H2SO4) = 0.0232 mol NaOH.

Answer 14

Since there was 25.00 mL titrated, the concentration in molarity is 0.0232 mol/0.025 L or 0.928 M.

Answer 15

Since the concentration of a strong base is equal to the concentration of the OH-, pOH = -log(0.928) = 0.032
14-pOH = pH
14-0.032=13.97

Answer 16

Does that help?

Answer 17

Yes it does. Thanks a lot!

Answer 18

No worries. Happy studies!

Answer 19

You too!

Answer 20

Ah, refreshed my memory of what to do with tirtation, little question, what do I do if the substance isn't a strong acid or base?

Answer 21

You 'll need the Ka of the weak acid or Kb of the weak base, an equilibrium reaction, and an initial/change/equilibrium table.

Answer 22

Titration is a laboratory technique by which we can determine the concentration of an unknown reagent using a standard concentration of another reagent that chemically reacts with the unknown. This standard solution is referred to as the "titrant". We have to have some way to determine when the reaction is complete that we are using. This is referred to as the "end point" or more technically the equivalence point. At that point all the unknown has been reacted with the standard titrant and some kind of chemical indicator must let us know when that point has been arrived at.

At the equivalence point:

Number of equivalent weights of titrant = Number of equivalent weights of unknown

or
(Normality of the titrant)(Volume of titrant required to reach end point) = (Normality of unknown) (Volume of unknown)

Generally we know the Normality of the titrant since it is a standard solution. We also pre-measure the volume of the unknown. We then titrate with the standard from a buret into the container with the measured unknown and the chemical indicator until the indicator either turns color or a precipitate indicates that the end point or the equivalence point has been reached. Having the initial and final readings of the titrant buret gives us the volume of the titrant used. The only unknown in the above equation is the Normality of the unknown.
Asker's Rating & Comment

Answer 23

Well that really clears up any loose ends and doubts I had. Thanks a lot for the help!