Materials: Brown sugar-aq, activated charcoal such as is sold for use in aquariums, glass wool, gas holder SD-17-V. Procedure: Same as in preceding demonstration, excepting a dark brown aqueous solution of sugar is used in place of methylene blue. Observations: The brown coloring matter in the sugar is removed by the activated charcoal, leaving a very light-brown solution in cell 2.
Note : A large sugar refinery will consume several tons of bone charcoal per day in decolorizing brown sugar by this method.
Dem. 488-Effect of Pdicle Size on Adsorption R d e on Carbon
Experiment developed by Alphonse Palermo. To show: Rate of adsorption as a function of size of particles of adsorbent (activated charcoal). Matm'als: Lumps of activated charcoal; methylene blue-aq, H-3,20-mm funnel with filter paper. Procedure: Project three culture tubes two-thirds full of methylene blue-aq in H-3. Take two pieces of activated carbon of equal size. Drop one into tube 8. Coarsely powder the other, blowing away fine dust. Drop the lumps into tube S. Shake tubes 8 and S together for 15 sec. Replace tube 8 in H-3. Filter the solution in tube S into another culture tube and put into H-3. Observations: Tube I is dark blue, tube 8 blue, tube S colorless. The finer particles of carbon absorb the dye much faster. Reference: (1949).
HAUSER, E. A,, J. CHEM.EDUC.,26, 566
B. Carbon Monoxide Dem. 489-Formoth
+
+
+
Materials: Formic acid, conc. HzSO4, H-1 with delivery tube replaced by a 1-mm capillary 2 in. long.
+
2 Procedure: Project H-1 containing 2 ml HCHO rnl conc. H.BOa, and the capillary exit tube in place Heat gently, stopping as soon as bubbles come off in quantity. Ignite escaping gas. Hold matchhead in the flame. Observations: Bubbles of CO rapidly evolve, and can be ignited at the capillary tip. The blue flame there is invisible (exhibit macro) but will ignite a matchhead.
/
Dem. 490-C02
from Dry k e
Experiment developed by August J . Colo. To show: ice.
A simple C02 generator employing dry
Materials:
G-1, dry ice, limewater.
Procedure: (a) Put 10 ml warm water into G-1 generator compartment, and two-thirds fill the receiver compartment with tapwater. Project. Drop small lumps of dry ice into the generator and stopper. Insert gas holder, collect CO,. (b) Raise a lighted match into the COXgas. (c) Add a dropperful of clear limewater to the receiver compartment. Observations: (a) A lively evolution of COa occurs. (b) The lighted match is extinguished in COe. (c) CaC03 precipitates.
Dem. 491-C02
To show: HC1.
from Limestone and Acid ( I )
A simple Cop generator, using CaC03
+
Materials: G-1 or G-2; lumps of limestone from petshop, 6N HC1, limewater. Procedure and Observations: (a) Using GI. Place five 3-mm3 lumps of limestone in the generator compartment, water in the receiver and HC1 in the dropper. Project. Add acid dropwise. Catch COzand test as in preceding demonstrations. (b) Using G-4. Fill the compartment bearing the valve half-full of limestone chips. Half-fill the open compartment with HC1. To use, open the valve: the acid runs into the other compartment, reacts with the limestone and generates C02. The culture tube of G-2 can be half-filled with limewater to test for the Cot. Upon shutting the valve, the pressure of Cot being generated forces the acid back into the open compartment and off of the limestone chips, thereby arresting the generation of gas. (3-4 is a simplified Kipp generator.
Dem. 492-C02
conc. To show: Preparation of CO from HCOOH H2S0,. HCOOH conc. Hz804 -+ HzSOn.Ht0
A326
1. PREPARATION OF C 0 2
of Carbon Monoxide
Experiment developed by August J . Colo.
co t .
C. Carbon Dioxide
Journal of Chemical Education
from Limesfone
+ Acid (2)
Experiment developed by August J. Colo. To show:
Formation of COa from acid
+ CaCOa.
Materials: H-3, limestone, dil. HC1, benzene, cottontipped swab. Procedure: Project H-3 holding 2 g limestone in culture tube. Drop in dil. HCl until good evolution of gas occurs. Now put a couple of drops of benzene on the cotton swab, light it, and lower it into the culture tube. (Or the projector lamp can also be turned off and the room darkened.) Observations: C02 is evolved. The benzene burns with a smoky flame which projects well; it is extiuguished by the COzin the culture tube.
