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Titration curves and buffering capacity (with the Cobra3Chem-Unit)

Product No: P3061640

Principle:

pH values can be measured with the aid of electrochemical measurements and proton-sensitive electrodes (e.g. glass electrodes). By combining a glass electrode with a reference electrode in one housing, a single-rod glass electrode, which is appropriate for acid-base titrations, is created. The titration curves allow an exact determination of the equivalence point in titrations of strong and weak acids and bases.

Tasks:

Determine the titration curves of different neutralisation reactions.
Determine the titration curve of an ampholyte (glycine).
Determine the buffering capacity of various aqueous acetic acid/sodium acetate mixtures at different total concentrations.

What you can learn about:

Strong and weak electrolytes
Hydrolysis
Dissociation of water
Amphoteric electrolytes
Isoelectric point
Law of mass action
Indicators
Glass electrode
Activity coefficient
Buffering capacity
Henderson-Hasselbalch equation

Materiallist (Excerpt)	Product	Amount
Set of Precision Balance Sartorius CPA 623S and measure software, 230 V	49224-88	1
Cobra3 Chem-Unit, USB	12153-50	1
Software Cobra3 Chem-Unit	14520-61	1
Immers. probe NiCr-Ni, teflon, 200°C	13615-05	1
Magnetic stirrer Mini / MST	47334-93	1
pH-electrode, plastic body, gel, BNC	46265-15	1
Buffer solution, pH 4.62 1000 ml	30280-70	1
Buffer solution, pH 9 1000 ml	30289-70	1
Retort stand, h 750 mm	37694-00	1
Power supply 12V / 2A	12151-99	1
Burette, lateral stopcock, Schellbach, 50 ml, graduations 0, ml	36513-01	2
Burette, lateral stopcock, Schellbach, 25 ml, graduations0,05 ml	36506-01	1
Holder for two electrodes	45284-01	1
Burette clamp, roller mount.,2pl.	37720-00	1
Caustic soda sol.,1.0M 1000 ml	48329-70	1
Hydrochloric acid, 1.0 mol/l, 1000 ml	48454-70	1
Sodium acetate, anhydr. 250 g	31612-25	1
Water, distilled 5 l	31246-81	2
Acetic acid, 1 M sol., 1000 ml	48127-70	1
Volumetric flask 1000ml, IGJ24/29	36552-00	4
Pipette dish	36589-00	1
Ortho-phosphoric acid 85% 250 ml	30190-25	1
Glycocoll /glycine/ 100 g	31341-10	1
Data cable, plug/ socket, 9 pole	14602-00	1
Volumetric flask 500 ml, IGJ19/26	36551-00	1
Pipettor	36592-00	1
Volumetric flask 250 ml, IGJ14/23	36550-00	7
Pasteur pipettes, 250 pcs	36590-00	1
Spring balance holder	03065-20	1
Weighing dishes, square shape, 84 x 84 x 24 mm, 25 pcs.	45019-25	1
Right angle clamp	37697-00	1
Volumetric pipette, 50 ml	36581-00	5
Volumetric pipette, 25 ml	36580-00	5
Rubber caps, 10 pcs	39275-03	1
Glass beaker DURAN®,tall, 150 ml	36003-00	16
Glass beaker DURAN®, tall, 250 ml	36004-00	1
Glass beaker DURAN®, tall, 100 ml	36002-00	1
Glass beaker DURAN®, tall, 50 ml	36001-00	3
Funnel, glass, top dia. 80 mm	34459-00	3
Spoon, special steel	33398-00	1
Funnel, glass, top dia. 55 mm	34457-00	2
Volumetric pipette, 2 ml	36576-00	1
Magnetic stirring bar 30 mm, cylindrical	46299-02	1
Wash bottle, plastic, 500 ml	33931-00	1
Volumetric pipette, 1 ml	36575-00	1
Graduated pipette 10 ml	36600-00	1
Graduated pipette, 1 ml	36595-00	1
Laboratory Experiments Physics, Chemistry, Biology andApplied Sciences, CD-ROM, incl. operating manuals	16502-42	1