In order for me to obtain the value of 'n' in the formula: (CH2) n (COOH) 2To work out the value of 'n' I will need to carry out an experiment known as a 'titration'

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In order for me to obtain the value of 'n' in the formula: (CH2) n (COOH) 2

To work out the value of 'n' I will need to carry out an experiment known as a 'titration'. A titration is a very common technique used in chemistry, it is a practical procedure for accurately measuring the volumes of solutions which chemically react together and can also be used to calculate the number of moles of a substance which is present.

In order for me to complete the titration I will need the following apparatus:

* 100cm3 beaker

* 250cm3 volumetric flask

* stirring rod

* top pan balance

* a 25 cm3 glass pipette

* a pipette filler

* a 50cm 3 burette

* a burette clamp

* a clean dry 250cm3 beaker

* label for each solution

* a clean dry small funnel

* 250cm3 conical flask

* distilled water

* Prepare a standard solution

The first thing I will need to do is prepare a standard solution for the titration because titrations can only be done with liquid solutions and as I have got a solid Dicarboxylic Acid I will need to covert it into liquid form.

In order to prepare the standard solution I will first need to weigh out the acid to 2g so that the titration will be accurate, as if I use more or less acid then this would affect my results and would make my titration results unreliable.

* To weigh out the acid I will first adjust the scale to zero with the 100cm3 beaker on the top pan.

* I will then place the acid into the beaker using a spatula ensuring that I put exactly 2g of acid to 2 decimal places, so that on the scale it would look like 2.00g

* Next I would pour 50 - 100 cm3 of distilled water into the beaker with the solid acid

* Stir the mixture with a stirring rod until all the solid pieces are completely dissolve. When all of the solid pieces are dissolved rinse the stirring rod with distilled water so as to wash away any of the mixture of the solid on the rod into the solution.

* I would then pour the liquid into a volumetric flask, ensuring that I don't spill any of the solution otherwise I would have to start all over again.

* I will then fill the volumetric flask with distilled water until the mark on the flask (250cm3), certifying that the water is filled up to the mark at eyelevel from the bottom of the meniscus.

* Finally I will put the stopper on the volumetric flask and shake it well to make sure that the solution is mixed thoroughly.

I now have a solution ready for titration, I will put a label marked 'Dicarboxylic Acid' and stick it on the flask. I have a fair amount of this solution so that it is enough for about 3 titrations with some remainder liquid left for the cleaning of the equipment
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In the other 250cm3 beaker I will pour the alkali solution in this case sodium hydroxide (NaOH) and label that beaker 'sodium hydroxide' with w sticky label.

For an accurate titration to take place I will first need to clean the equipment.

* Cleaning equipment

* Firstly I will take the glass pipette and place the pipette filler on top of the pipette.

* Then I will fill the pipette halfway with the Dicarboxylic Acid and take it to the sink. I will tip the pipette horizontally and remove the filler carefully.

* ...

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