Indicative universal paper. Dissolve 10 mg of phenolphthalein, 20 mg of methyl red, 40 mg of bromothymol blue and 50 mg of thymol blue in 88 ml of methanol. Add some drops of solution of sodium hydroxide slowly until the solution remains orange reddish, and then submerge the filter paper in this solution. Once soaked, take out it, drain it and allow drying. Finally cut it in ribbons.

Virage: PH= 2 red colour

PH= 4 orange

PH= 6 yellow

PH= 8 green

PH= 10 blue

Red congo paper. Dissolve 50 mg of red Congo in 50 ml of water, adding some drops of ammonium hydroxide. Submerge the filter paper in this solution, and then dry the paper in an atmosphere without vapors. The mineral acids color it of blue and the organic strong acids of violet. Virage of PH= 3- 5.

Starch iodic paper. Mix 0.1 gr of pure starch with 1.0 ml of cold water carefully, then pour slowly and shaking this mixture in 20 ml of hot water. Boil the mixture during some minutes, cool it quickly. Later add 20 mg of I Iodide of Potassium and 10 mg of I Iodide of Cadmium. When everything is dissolved, submerge the paper filter, once very soaked dry it in an atmosphere free of vapors. The solution is unstable, for what you should prepare little before using.

Use like indicator of nitrous acid, halogens and other agents oxidizers. Plans of a drop or vapors of oxidizer put blue-violet and an excess of brown color.

Paper acetate of lead.- Submerge a paper filter in a solution of 50 mg of acetate of lead (or nitrate) in 10 ml of water. Dry the paper in an atmosphere free of sulfhídric gas. This paper with the vapors of sulfhídric acid gives a brown coloration.

Litargirio-glicerine. Add litargirio to a mixture of 6 parts of glycerin and a to three parts of water, until the mixture acquires the wanted consistency and place it carefully on the material that wants to hit. The addition of iron oxide or sand finely milled slowly the time of forging and it diminish the appearance of brittle zones. This cement is resistant to the acids.

Cement of Dekhotinsky. Case one mixture of 70 parts rubber orange lacquer with 30 parts of pitch of pine (rosin), the fused material one could pour in appropriate molds in order to have it in bars.

Cement of Jackson. Dissolve 3 parts of raw rubber in a mixture fused of 1 part of asphalt and 6 parts of pitch (rosin). Maintain the fused mixture for 2-3 hours. Leave it cool, add you a part of paint thinner and model the mixture in bars.

Paste of starch.- Mix ½ cup of flour and ½ ounce of alum. Add water until form a thin paste (two cups), boil the mixture 5 minutes. Add a half-gram of phenol.

Solution of Bredemann in order to loosen unions of glass.- Mix 10 parts of hydrate of chloral, 5 parts of water, 5 parts of glycerin, 3 parts of hydrochloric acid to the 25%.

The piece that is wanted to loosen submerges or covers with this mixture, leaves several hours or days until is loosen. The liquid could use again.

Magnetic agitator. In the center of the arrow of a motor of old phonograph (115 volts, 60 cycles) or another synchronous motor, a magnetic bar is placed. The motor and the bar close up inside an aluminum box. The agitators are improvised containing pieces of alnico inside a Pyrex tube or containing them in a piece of tube of Teflon and closing it with some clips heated to 500º C.

Rings in order to sustain recipients of spherical bottom.- they are improvised cutting a hose of rubber and joining the ends by means of another minor tube.

Take off for globules of mercury. With nitric acid clean a helical of copper, then introduce it in mercury in order to form a covered with amalgam. When the hairspring moves on the globules of mercury these adheres to the surface; shake the hairspring in intermittent form inside a flask for leave off the mercury.

Infrared light. The infrared ordinary lamps one could use for reflux or distill solvent that boils up to 80oC. Also in order to make filtrations in hot.

Chloride of copper (I). Dissolve in 200 ml of water, heating if it is necessary, 62.5 gr of cupric-pent hydrated sulphate and 16.25 gr of sodium chloride.

To the solution warm it t add, shaking in 4-5 minutes, a solution of 13.25 gr of sodium bisulphite, or the equivalent of crystallized sodium sulphite and 8.8 gr of sodium hidroxide in 100 ml of water. The solution should remain almost colorless. She mixes cools in bath of ice and decant the liquid the cuprous chloride precipitate is washed twice with water freeze that contains a little of sulfur dioxide. The washed material is separate for decantation. The cuprous chloride, humid, is dissolved in 100 ml of hydrochloric concentrated acid. This solution should stay in a close recipient and use before 24 hours. Almost quantitative yield.

Amalgam of zinc. A mixture of 50 gr of zinc powder or limalille, 3.8 gr of chloride of II mercury, 2.5 ml of hydrochloric concentrated acid and 2.5 ml of water becomes agitated for 25 minutes.

The watery solution decants and to the amalgam of zinc adds 37.5 ml of water and 50 ml of hydrochloric concentrated acid. If is going to use this mixture in order to reduce a compound, add 0.22 moles of the substances that you want to reduce immediately.

Aluminum amalgam. In an Erlenmeyer flask of one liter is placed 25 gr of pieces of aluminum sheet of 10 cm of long, 2.5 cm of width and about 0.5 mm of thickness, they then cover with a solution of sodium hydroxide at the 10%.

The flask warms in water bath until have come off hydrogen vigorously for some minutes. CAUTION could BE FORMED EXPLOSIVE MIXTURES. Then the sheets wash first with water abundantly and then with ethanol, achieving a clean surface for amalgamation. So add enough solution of Chloride of II Mercury at the 2% in order to cover the whole surface. After two minutes the attack is suspended, decant the solution and the amalgam washes with water, later with ethanol and finally with humid isoproipilic ether, keeping the amalgamate in 150 ml of isopropyl ether.

Lead Tetracetate. In a round bottom flask of 500 ml with three necks, provided of a thermometer and an agitator, mix 275 gr of acetic glacial acid and 92.5 ml of acetic anhydride. Mixed and heat to 55º C, shaking and adds in portions of 10 gr a total of 150 gr of red oxide of lead (minio). Each addition is made after the color of the previous addition has disappeared and the temperature is under 65º C.

Almost at the end of the reaction is needed to heat the flask up to 80oC in order to complete the reaction, Do it with caution.

The dark solution cools down, the lead tetracetate filters. Concentrating the liquors mothers and passing them dry chlorine you obtain a second crop.

The precipitate washes with cold acetic acid, and later are dissolved in a mixture of acetic glacial acid with a little of acetic anhydride. The solution is clarified in hot with activated coal (norite), Filter in hot and cool down. The colorless crystalline product dries off to the hole on KOH. Yield 75 gr.

The lead tetracetate exposed to the air take a brown color. The material strongly colored could become purified dissolving it in acetic hot acid with activated coal (norite).

In a kitasato flask put the necessary amount of potassium permanganate. Connect with a funnel of separation, whose exit is prolonged until the bottom, and put diluted HCl (1: 4). The chlorine goes over to a flask with water and then to another with sulfuric acid, later to an empty flask and lastly to the means of reaction. A T tube is used as valve of security. To the end the chlorine with a current of carbon dioxide crawls, are generated in the same apparatus adding carbonate of calcium well crushed instead of the potassium permanganate.

Powdered copper. Dissolve 100 gr of cupric pent hydrated sulphate in 350 ml of hot water. Allow to cool the solution and when arrives to 25-30oC begins to shake and add 35 gr of powder of zinc. The addition is slow and is continued until total fading of the solution.

The precipitate copper washes with water. Add to the precipitate copper hydrochloric acid to the 5% in order to eliminate the excess of zinc. Care, it comes off hydrogen.

You must become agitate until the detachment of hydrogen cease. The powder of copper is picked up for filtration, washed with water and stay how humid paste in a flask very close.

Silver oxide. Dissolve 17 gr of silver nitrate in the minimum amount of distilled water and add it shaking 4 gr of sodium hydroxide dissolved in 10 ml of water. Filter the silver precipitate oxide and wash it with hot water.

Persulfuric acid. Mix 10 gr of potassium persulfate milled with 11 gr (7 ml) of sulfuric concentrated acid previous cooled in a mortar.

In absence of water is stable. Use it in suspensions or solution with acetic acid and in sulfuric diluted acid (add 40-50 gr of ice).