CHAPTER I. 

 STANDARD ACID AND ALKALI 



1. Calibration of Pipette. Boil distilled water, allow to cool 

 somewhat and pour carefully into a small vessel which can be 

 closely stoppered. Cool to the temperature of the weighing 

 room. Clean a 25 or 20 c.c. pipette carefully with cleaning fluid 

 and rinse thoroughly. Weigh to the third decimal a carefully 

 cleaned weighing bottle of small size. With the pipette, measure 

 exactly 25 or 20 c.c. of water, which should be at room tempera- 

 ture, into the weighing bottle, stopper quickly and weigh. The 

 difference gives the weight of water delivered by the pipette. 

 Weigh at least three portions. Take the temperature of the 

 water (this should be that of the room). Assume that 1 c.c. of 

 water at room temperature weighs 0.997 grams. Calculate the 

 volume of the pipette. Paste a label on the calibrated pipette 

 and write on it the volume delivered at the specified temperature. 



This method of calibration may be used for pipettes of any 

 size, provided that the total weight does not greatly exceed 

 100 gms., which is the largest amount which should be weighed 

 on the quantitative balances. 



2. Empty* your burette exactly to the 50 c.c. mark. From 

 your pipette, run in 25 (or 20) c.c. of water and note the level. 

 Repeat the process, thus calibrating the burette. By emptying 

 the 5 or 10 c.c. pipettes into the burette in a similar manner, 

 calibrate them. 



3. Normal Acid and Alkali. A normal solution of an acid 

 is of such strength that one liter of the acid will contain one 

 gram equivalent of ionizable hydrogen (1.008 g.). A liter of 

 normal hydrochloric acid thus will contain a weight of hydro- 

 chloric acid gas equal to its molecular weight, since this amount, 

 36.46 g., will contain the desired amount of hydrogen. If sul- 



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