Bachiller

Experiment 34 Fecha: 7-6-12
Measurement of the active ingredient in aspirin pills
Aim
1 The ratio of filler toactive ingredients in common aspirin tablets is to be appreciated.
2 The techniques of quantitative separations are to be learned.
Equipment, materials, or reagents
1 Aspirin tablets
2 Mortar andpestle (100-mL capacity)
3 95% ethanol
4 Filter paper (Whatman no. 2, 7 cm)
5 Balance
6 Drying oven at 110_C
7 Hanus iodine solution
8 Microscope slides
9 100-mL beaker
10 25-ml beaker
11Rubber policeman
12 Vacuum filtration setup (Büchner funnel; 250-mL filter flask)
Procedures
1 The actual weight must be recorded on your Report Sheet.
2 The number of tablets must be counted andrecorded on your Report Sheet.
3 The weighed aspirin tablets should be placed in a mortar of approximately 100 ml capacity.
4 Before starting to grind, the mortar should be placed on a white sheet ofpaper and loosely covered with a filter paper.
5 The aspirin tablets should be broken up by being gently hammered with the pestle.
6 A vacuum filtration apparatus should be set up.
7 With the aid of arubber policeman, the supernatant liquid and solid from the mortar must be transferred to the Büchner funnel.
8 When about 1 ml. of clear filtrate has been collected in the filter flask, the watershould be turned off and the Büchner funnel lifted, and a drop of filtrate should be allowed to fall on a microscope slide.
9 Procedures no.4 must be repeated two more times; a total of 40 ml. ofethanol are to be used in the four extractions.
10 After each extraction it must be reported if the extract carries acetylsalicylic acid.
11 These observations must be entered on your Report Sheet (4,5, and 6).
12 When the filtration is completed and only the white, moist solid is left in the filter, the filter paper with its contents must be transferred into 100 ml beaker and place and the...