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Slide 1

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By Charlotte Cooper…read more

Slide 2

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What is titration?
· A titration is a quantative (find out the quantity) technique based on
measuring the volumes of solutions that react with each other.
· In titration, one solution (solution 1) is added to another solution
(solution 2) until a chemical reaction between the components in the
solutions has run to completion. Solution 1 is called the titrant, and
we say that it is used to titrate solution 2. The completion of the
reaction is usually shown by a change of color caused by a
substance called an indicator.
· Chemists use titrations to measure concentrations and to investigate
the quantities of chemicals involved in reactions.
· Titrations are widely used because they are quick, convenient,
accurate and easy to automate.…read more

Slide 3

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· In a typical titration, a pipette or burette is used to transfer a
set volume of liquid to a flask.
· Indicator is normally used because it will change colour when
the right amount of alkali has been added to react with all
the acid. IT works because there will be a sharp change of
PH at that point.
· The acid is run into the alkali a little at a time until the
indicator changes colour to neutral or green. This is the end
point, when you should stop adding the titrant.
· Reading the burette scale before and after the titration shows
the volume of alkali added.…read more

Slide 4

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· The accuracy of a titration can be no better than the accuracy of the
solutions used to make the measurements. If chemists know the
concentration of a solution accurately, they call it a standard
solution, because it can be used in analysis to measure the
concentrations of other solutions.
· E.g. First they would accurately weigh the sodium carbonate, then
dissolve the solute in a small amount of solvent, warming if
necessary.. It is then transferred into a graduated flask and all the
solution is rinsed into the flask with more solvent. The solvent is then
added drop by drop to make up the volume mark on the flask before
the stopper is added and the flask shaken.…read more

Slide 5

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Accuracy cont...
· To be accurate, it is common to do a rough titration first to get an
idea of where the end pint lies so a more accurate titration can be
done afterwards.
· The analyst repeats the titration two or three times as necessary to
achieve consistent values for the value of alkali added.…read more


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