# TITRATION!

How to carry out a titration and the equations for finding the unknowen.

if you already have a method REVISE THAT this will just confuse you if your methods different!

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## Firstly, ACIDS AND ALKALIS

Acids and Alkalis are classified by the extent of their ionisation in water :0

If an acid or alkali is COMPLETELY IONISED or VERY IONISED in water then it is said to be strong.

If an acid or alkali is PARTIALLY IONISED in water it is said to be weak.

The CONCENTRATION is also important. THE CONCENTRATION OF AN AQUIOUS SOLUTION IS USUALLY EXPRESSED BY STATING HOW MANY MOLES OF THE SOLUTE THERE ARE IN EACH CUBIC DECIMETRE OF THE SOLUTION! The concentration and the strength both contribute to the pH; so you can have an acid with a strong concentration and the same acid with a weaker concentration and the strong one would have a lower pH. :)

STRONG ACIDS REACT MORE VIGOROUSLY WITH METALS TO PRODUCE METAL SALTS AND HYDROGEN!

DONT FORGET! One cubic decimetre=1000cm^3 or 1 litre :)

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## CARRYING OUT A TITRATION!

Firstly measure your acid or alkali of known concentration, so that you have a reasonable volume of it (not loads, not a tiny drop). Put this into a conical flask and add some indicator (eg.phenolphthalein) and place it onto a white tile so you can see the colour change in the experiment.

Secondly, fill your burette (you would wash this carefully and rinse it with the acid or alkali your going to fill it with first) with your acid or alkali of unknown concentration. MAKE A NOTE OF THE INITIAL VOLUME!

Slowly drip the liquid from the burette into the conical flask, swirling it carefully as you do. As soon as you see a colour change stop dripping and make note of the volume of unknown that went into the conical flask.

DO THE CALCULATION (next card)

PSSSST!.. For an extra mark in a big titration question, mention repeating the test, by running the tap until just before your previous volume has gone into the conical flask, then slowly dripping to get a more ACCURATE result!

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## CALCULATIONS :(

Just remember BIG red nerdy frogs :)

Balance the equation

Ratio- extract from the balanced equation

Number of moles (in the solution of known volume and conc)multiply this by the ratio for each one (if its 1:1 one you obviously dont need to, but always do anyway so you dont forget if its not 1:1)

Formula!:

concentration of solution = No of moles of solute/volume of solution

AN EXAMPLE ON THE NEXT CARD!

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Big Red Nerdy Frogs :)