О производстве спичек

Experiences with egg


The Scene is in the manner of cabinet of the chemistries. There is a table, a black board. There is chalk and wet rag on it. There is a marble stone and chlorine acid for taking the carbon dioxide, 100 ml concentrated mixture of potassium , one liter of the chlorine acid (1:2) concentration, a cone retort with the size of egg, a small pail or, 2 kg unused lime, a well boiled egg,2 not boiled egg ,a pail water. 1liter glass, with tweezers on it. Pupils 8 classes Dilbar, San and Hadicha are preparering the experiences.
In hurrying the pupils 7 classes Odil and Pulat enter the scene
Odil: Dilbarhon, where is our techer?
Dilbar: Right now she left; she may be class for teachers.
San: why are you so hurrying?
Hadicha: what do you want?
Odil: We wanted to ask some questions.
Hadicha: Ask the questions, may be together we shall solve.
Pulat: What are you doing?
Dilbar: We are going to do some experiences from chemistry.
Sanam: What do you want to ask?
Hadicha: Ask your question, may be we answer to your question.
Odil:Do you know Karim which learns in 7 "A"?
Sanam:Yes,
Odil: Yesterday Karim asked if we want to find an answer of his questions from chemistry.He asked us if there was any way to cook egg without electricity, fire.
Hadicha: is that all?
Pulat: No, he also gave several questions. To answer them we decide to examine all pages of the book. But we have not been able to find the answers to all these questions.
Odil: To know it finally we decided to ask it from our teacher so we came here.
Dilbar: Have you read about "Oxidizes, basis and salts" from chemistries.
Pulat: We passed Oxidizes, basis and acids, but salts on following lesson.
San: If you read them you must solve this problem.
Pulat: Do you know this?
Dilbar: Yes, we know this
Pulat: If you know tell us.
Hadicha: Not only we’ll answer, if you want we can show this on experience.
Pulat: Please do it.
Dilbar( Showing the egg , which is on table ,to Pulat) find among these eggs not boiled egg
Odil: Is there not boiled egg among them?
San: One welded two damp eggs.
Pulat: How can I know if they are boiled or not?
Hadicha: Didn’t you know this?
Dilbar: It must be taught you on physicist. At first if you turn round the not boiled egg, it can`t move.But boiled can easily turn round in the second if you take not boiled egg and put it on light.It can show the light. The boiled egg does not pass the light.
Pulat: (Turned round the egg on table, then looks at light and separates the not boiled egg and returns Dilbar): these two, are not boiled and gives it..
Dilbar: (puts pail pawns 2 kg quicklime, then places the not boiled egg, add 1, 5-2 litres of water, at that time water begins to simmer)
Do you see it? After some minute egg will be ready
Odil: Dilbar did you added a lime to the pail?
Sanam: You she added quicklime.
Dilbar: B y pouring a water into quicklime, we formed a simple lime.
Pulat: When we have studied oxidizes and their chemical characteristic really saw that big heat energy stands out under this reactions.
Dilbar: It is correct.
Odil: So we know about forming the big heat in these reactions, but do not think to use it for boiling egg.
Hadicha: After boiling eggs will be ready. (Dilbar takes egg from pail with tweezers, washed it in the water, one gave Pula, other to Odil. They turn round egg on table and look at light and believe on that it is boiled. Pulat even cleaned from shell shows the egg to others.
Pulat: It is a good work (the girls laughed)
Odil: Now I want ask you the second problem, I think you can help us to solve it.
Sanam : Please.
Odil: Is it possible to take out eggs not having damaged egg from the shell of it?
Dilbar: This is possible do it on base of chemical characteristic of acids.
Pulat: If you explain this also on experience, it will be good.
Dilbar: Sanam show this experience please you.
Sanam: Well (Sanam pours 500 ml of mixture of salt acid (1:2) into chemical glass and puts one boiled egg there. In the beginning the egg lowers down, but then surfaces up, and this action repeated, from this stand out the gas).
Odil: Sanam, this egg dance in water.
Sanam: It is not water in the glass.
Hadicha: Thisis solution of the salt acid.
Odil: Why have you put the egg in salt acid?
Sanam: The Shell of egg basically consists of carbonate calcium and partly organic material so strong part of shell salt carbonate calcium salt keeps the strong of the shell, but from chlorine acid it begins to dissolve: One of the characteristic of the acids is, from the reaction between acid and salt will form the new salt and acids.
Pulat:We also know it.
Pulat: What does it mean? Why egg rises up and lowers down? (Dilbar is mixing the acid in glass)
Sanam: Because the chlorine acid enters in reaction with carbonate calcium which is in the shell. Hadicha the equation of reactions on board:
CaCO3 + 2HC1 = CaCl2 + H2CO3.
Sanam: (showing the equation): reactions is formed calcium chloride salt ,which can dissolve in spite of calcium acid ,which can’t dissolve and it dissolve in water . From this it becomes unstable and quickly disintegrates
( Hadicha writes the equation of reactions):
H2CO3 = H2O + CO2.
Dilbar: whjen we put the egg in glass ,there appeared the gass , it was carbon dioxide.a balls of carbon dioxide gas ,which is formed under the the egg, rises it up,when egg turns round the gas goes out and the egg lowers down again Understandable?
Pulat and Odil: We have Understood (At this time, a big part of shells dissolves and there will be only the egg. Dilbar takes the egg from glass and gives Pulat and Odil and shows to spectator.
Dilbar: So, there is not a shell, if the shell is not dissolve completely, you should put them in a acid a little, and the shell will dissolve. Have you understood?
Pulat: have Yes we have understood. Now answer the third question
Dilbar: So, let’s listen the third question.
Pulat: How the retort, which is smaller than the boiled egg without the sell, can swallow it.
Hadicha: This is simply.
Odil: All seems you simple.
Dilbar: Hadichahon show him this experience.
Hadicha: Well, presently (looking at Pulat).The Answer is of this question is possible to find from chemical characteristic of the alkalis. If you know at reactions of the alkalis with acid oxides are formed salt and water. For example: from the reaction of potassium and carbon dioxide is formed potassium dioxide salt and water. (She asked to Sanam write this on board and Sanam write this 2K0H + CO2 = K2CO3 + H2O.
Odil: we know this. Can you tell me ( taking the cleaned boiled egg from table and puts on the retort ) How small retort can swallow the big egg?
Hadicha: Watch (Hadicha takes egg and full the retort with gas ,using the kip instrument and puts egg on retort again, but the egg stands as cover.
Pulat: What you have you filled the retort.
Hadicha: I have filled retort with the carbon dioxides. Now you will see how the retort will swallow the egg.
Odil: Where, flask has not swallowed the egg.
San: I think the retort has no flasks no appetite today, let’s gives it a little "vinegar" for appearance of the appetite
Hadicha: You are right. (She takes the egg from the retort and adds vial in retort a little liquids, quickly closes the retort with egg. The Egg immediately slowly, growing begin to fall into the retort, and finally fell on bottom of the retort.) Well have you seen? ( Pulat and Odil smiling have looked to each other).
Pulat: We have seen, but the reason of these phenomena is not understandable
Hadicha: It is easy, have you seen how I have filled the flask with carbonate dioxide gas. I have added concentrated a solution of acerbic potassium instead of vinegar. The Carbonate anhydride enters in reaction with acerbic potassium (shows the equation to reactions). The pressure of gas shortes, thus the pressure in the retort shortes, The pressure of the air out of retort is stronger than the pressure of the air inside the retort, thus the air pushes the egg from all sides and puts it into the retort. Have you understood?
Odil and Pulat: yes.
Odil: Thank you very much.
San: Is there any questions?
Pulat: No.