School chemical project. Speech "Research work of students in chemistry
Research
TOPIC: Detergents for dishes and their properties. The effect of detergents on metal corrosion.
Introduction p. 2-3
Chapter 1. General Information on Dishwashing Detergents p. 4-5
1.1 Dishwashing detergents p. 4
1.2 the Composition of dishwashing detergents p. 4-5
Chapter 2. Diagnostics for dishwashing detergents p. 6-8
However, a comparison with other studies, such as law and medicine, shows that the study takes a lot of time, for example, an internship or special training for university studies. It’s harder to sacrifice the time that you have to sacrifice while studying in order to keep up. Lectures, exams and internships hold students for a semester and without lectures. Least of all students can afford a lesson on the side of time.
But the one who invests time is rewarded with a diverse and interesting study that offers a pleasant mixture of theory and practice. The most important prerequisites for obtaining a chemist's degree are interest and motivation! Prior knowledge in the fields of physics, chemistry, mathematics and biology is useful, but not a prerequisite, as knowledge can be developed with time and dedication. In addition, the analytical mind is important because the experimental results must be analyzed and interpreted, no contact problems with mathematics or English, patience and tolerance: if the experiment does not work today, maybe tomorrow.
2.1.Diagnosis of the use of dishwashing detergents page 6
2.2. Composition, properties and characteristics of the use of detergents p. 7
2.3. Physico - chemical properties of dishwashing detergents. pg. 7-8
2.4. Effect of dishwashing detergent solutions on page 8
the course of corrosion of iron objects.
Conclusion page 9
Also, don’t think about financing before starting research, because, as already mentioned, research and secondary jobs usually end. Always take the necessary precautions when working with chemicals in the laboratory.
Chemical research projects in the field of science use various types of analytical methods to determine the identity, composition and toxicity of various chemicals. There are several types of projects that a student or researcher can use to conduct chemical research, as well as a large number of methods, such as chromatography or mass spectroscopy. Elementary or high school students can use projects that use everyday objects, such as paper filters, to illustrate chemical methods.
References p. 10
Appendix page 10
Introduction
The twenty-first century is the time when information has become the foundation on which all spheres of human life rest. Therefore, each person must be sure that the information that he owns is reliable and will not bring him or others spiritual or physical damage. Streams of information reach us from everywhere, but the main source is the media. And often, even an educated and wise person with life experience cannot determine whether they are trying to deceive us using advertising tricks or just exaggerate the merits of the goods and services offered. Advertising has become an integral part of our lives. Sometimes it really helps to navigate the variety of goods and services, and sometimes it promises just “miracles”. Thanks to the active advertising policy of manufacturers, today almost every family uses special products for washing dishes. So, scientists have estimated that a Russian family of 4 people washes about 5 tons of dirty dishes every year! The first MS appeared more than 5000 years ago in the Middle East. But their role in our life has not changed so far. MS is currently used to remove various types of contamination: stains on clothes, rust, dirty dishes, etc.
Using vinegar, he creates a chemical study of the formation of hydrogen bubbles. Pour 15 milliliters of vinegar into a test tube or clear glass. Take a metal nail and pour the tip. Place the nail in the vinegar tube. Observe how bubbles form around the nail. These bubbles are made of hydrogen.
Perform thin layer chromatography using plants. Students or researchers can use this method to separate pigments from plants. Use plant leaves in small pieces to extract pigment. Put them in a mortar and add sand. Grind the leaves and add isopropyl alcohol with stirring. Place the solution in an indoor container. Cut silicon dioxide wafers into 1-8 cm strips for use in the experiment. A solvent solution is prepared using 100 ml of a paint diluent, 7 milliliters of hexane and 3.5 milliliters of isopropyl alcohol.
The composition of dishwashing detergents is close to shampoos, shower gels. That is, to hygiene products. And they have special security requirements. All this is good, however, dishwashing detergents are considered as household chemicals. This means that they do not need a hygiene certificate that guarantees safety. The requirements are that for a toilet cleaner, for dishes - the same. Manufacturers may subject their products to a safety test, but voluntarily. Chemists acknowledge: this certificate only guarantees that at the time of use you will not be poisoned, do not spoil your skin. But what happens over time in the body, into which the remnants of the detergent constantly fall, have not been investigated.
Take the capillary tube to the melting point and sprinkle a silica strip with a solution of plant extract. Repeat several times for a larger study surface. Dilute the strip two centimeters from the plant extract solution with a solvent solution. Observe the pigment as it disperses in the strip. Plant pigments have different solubilities, depending on the type of pigment. For example, chlorophyll B, which is yellowish green, is more soluble than xanthophilic pigments, which are yellow and orange, and will spread further along the strip.
With the ever-increasing number of new chemicals coming into circulation, actual problem is their study in order to obtain information on the potential hazard of substances and develop preventive measures to prevent adverse effects on the human body and the environment. Among a set of environmental factors subject to hygienic control, household chemical goods (TBH) deserve much attention in connection with their mass production and use, a variety of components that are part of the formulations, and also with a possible direct effect on the human body. As you know, after use, all chemicals enter the environment and adversely affect it, but we don’t think about it. Therefore, we decided to devote our work to household chemicals and, having studied the composition of MS for dishes, determine how safe their use is.
Experimental chemical experiments identify materials in substances obtained as evidence from the police. Forensic chemists can determine the composition, nature and source of material. Carries out a paper-based forensic chemistry project. Gather two pieces of filter paper and mark your initials near the edge of the paper with a pencil. Make a small hole in the center of the paper and use a black marker to form a small dotted ring around the hole. Fold the second piece of paper in half, then in four.
We believe that our work is very relevant today. We cannot do without MS, but their use often harms our world. To understand how to deal with the harm done to us by the MS, we must first of all learn more about them than is reported in the advertisement. We decided to conduct a study at our school in order to identify the funds that are most in demand and to analyze the reasons for the choice of participants in our study. Saying yes or no to MS is everyone’s business, but if certain rules are followed, then the health risk will be minimal.
Break the folds and use them to form two strands by folding them. Insert the rollers into the paper hole. Take a petri dish and fill half with water. Place the paper on a plate with a wick that points to water. Watch how water enters the wick, along the paper, carrying ink and sharing different colors. Write down the ink colors and indicate which ones are removed from the hole.
Chemical reactions with color
Conducts chemical studies of color changes. Observe chemical reactions by changing colors using combinations of different solutions. Mix about four different solutions with bottled water, such as potassium iodide, sodium thiosulfate, sodium hypochlorite, soluble starch. Add a few drops of two different solutions to the wells, indicating the solutions you are combining. Look at the color changes and which chemicals caused the reaction on contact.
Practical significance The work consists in the fact that the obtained information on the results of research can be used to educate the population of the village about the dangers of certain detergents, the negative impact of SMS on human health, and the increase in corrosion of metals from which plumbing is made.
To achieve a good result in chemistry on a large vestibular basis, it is fundamental that students know the concepts of radioactivity, stoichiometric calculation, and intermolecular bonds. The script is part of a series that will bring a study guide on one discipline per day.
Browse the ten most common topics. Bonds between atoms and between molecules: types of interatomic chemical bonds can be charged; intermolecular chemical bonds, their dependence on the polarity and geometry of molecules; and the effects of intermolecular forces. Colligative properties: Phenomena caused by the addition of solutes in some solvents. At high altitudes, will it be easier or harder to boil water? Water with dissolved solute, is it easier or harder to freeze? The question always arises about the system with the highest vapor pressure: water with 1 mol of salt or 1 mol of sugar?
purpose work: to study the physico-chemical properties of detergents, to investigate the effect of detergents on the corrosion of metals from which plumbing is made.
Tasks :
1. To study the literature on this issue;
2. Identify the most commonly used household detergent brands for dishes;
Train the calculation of both strong acids and bases, and weak acids and bases. Radioactivity: spontaneous radioactive releases, nuclear fission and fusion, and the half-life of radioactive elements. In more traditional vestibules, it is important to study the nature of alpha, beta, and gamma radiation.
Correct bid: interpret the half-life schedule. 
Chemical equilibrium: reversibility of chemical reactions, equilibrium constant and the formation of gaseous ammonia. From the equilibrium reaction, the vestibules will have to guess in which direction the equilibrium will shift if the concentration, pressure, temperature or amount of reagents changes.
3. To study the composition, data of dishwashing detergents, using their labels.
4. Investigate the physico-chemical properties of detergents;
5. Consider the effect of detergents on metal objects (nail).
Object of study : liquid dishwashing detergents.
Subject of study: properties and safety of the use of detergents for dishes, metal corrosion.
- Basic organic functions, nomenclature and recognition.
- Characteristics of organic compounds.
- Stack and electrolysis: the relationship between chemical reactions and electric current.
- Calculations of batteries and electromotive force.
- The amount of substance involved in these processes.
Hypothesis: if you have complete information about the composition and properties of detergents, then You can maintain human health, prevent damage to plumbing made of iron.
In accordance with the objectives of the study, methods of systematization of theoretical material, research methods and methods of observation, generalization of the accumulated material were used.
- Thermochemistry.
- The relationship between chemical reactions and the amount of heat.
- Exothermic and endothermic reactions.
Acid base catalysts - Operating hours: 39 hours Menu: Introduction, definitions and basic concepts, Structural study of acid catalysts - Base, Methods for producing alumina, oxides and zeolites, Modifications of basic acid catalysts. Characterization using various physical methods. The main reactions catalyzed by acidic solids.
Chapter 1. General information about dishwashing detergents
1.1 Means for washing dishes and their properties
Special dishwashing agents first appeared in the 1950s. Dishwashing liquid is available in the form of a liquid or gel. Gel-like products are considered more effective than liquid products.
The main properties of the product is its washing ability. A big plus of the product is its ability to effectively cope with oil and fat contamination in cold water, this is achieved by selecting the optimal surfactant composition.
Another important property of the dishwashing detergent is its gentle effect on the skin of the hands. It is worth noting that the statements of manufacturers that the pH level of their products is 5.5, in no way can guarantee the absence of irritation, especially in people prone to allergies. Therefore, when washing dishes, the skin needs protection. The product should contain emollients and do not forget that your hands can be protected from the harmful effects of the product with ordinary rubber gloves.
A lot can be said about the dishwashing detergent.
1.2 Composition dishwashing detergents
Detergents are based on surfactants. It is they who determine its washing ability.
Surfactants are divided into two types: ionic and nonionic (nonionic).
The fundamental difference is that nonionic surfactants are not subject to electrolytic dissociation, i.e. they do not decay in water into positively and negatively charged ions; ionic surfactants, when interacting with water, decompose into ions, some of which have adsorption (surface) activity, others (counterions) are adsorption inactive.
Ionic surfactants are called anionic if the surface-active ions carry a negative charge, and cationic if the surface-active positively charged ions. Some surfactants, depending on the conditions in which they are used, exhibit either anionic or cationic properties, therefore they are called amphoteric or ampholytic. Anionic surfactants - organic acids and their salts. Cationic - bases, usually amines, and their salts. In the global production of surfactants, most of the anionic substances.
Synthetic detergents necessarily contain a number of excipients that improve their washing ability. Detergent compositions sometimes include alkaline salts of weak inorganic acids (sodium carbonate and bicarbonate, sodium silicates, phosphates of various compositions), neutral salts (sodium chloride), peroxide salts, which have bleaching and disinfecting properties (sodium perborate and percarbonates). It is these chemicals that enter into chemical reactions with the metals from which plumbing is made, and the corrosion of metals occurs under the influence of these substances. Corrosion leads to billions in losses every year, and resolving this problem is an important task. The main damage caused by corrosion is not in the loss of metal as such, but in the enormous cost of products destroyed by corrosion. That is why the annual losses from it in industrialized countries are so great.
An important role is played by the organic components of surfactants: carboxymethyl cellulose, which prevents re-deposition of contaminants from the washing solution on the washed surface, and the so-called hydrotropes, which increase solubility and accelerate the dissolution of surfactants in water.
Some detergents contain enzymes that remove insoluble protein contaminants, organic bactericides, foam stabilizers.
Aromatic substances (fragrances) are added to many detergents, designed to eliminate unpleasant odors and give a washed surface a fresh aroma. True, the smell of apple, lemon or, for example, wild berries does not mean the presence in this product of extracts of the above fruits.
Also, dishwashing detergents may include substances that mitigate the negative effects on the skin of the hands. The most common supplements are glycerin, silicone, and herbal extracts. Glycerin and silicone have a similar effect, they create a protective film on the skin that prevents it from drying out. At the same time, the surface film created by silicone is able to protect against the penetration of substances harmful to the skin contained in the detergent.
Plant extracts soften the skin, have a calming effect, relieve irritation that can be caused by individual components of surfactants (for example, aloe vera milk has this effect). But even with all the undoubted advantages of these supplements, it is impossible to guarantee your skin complete safety.
Chapter 2. Diagnostics of detergents for dishes
Diagnosis of the use of dishwashing detergents.
In order to find out which of the means are the most used, we interviewed students, teachers and school workers. The survey involved 50 people.
Survey data show that the most popular is Fairy. It is used by 19 people among the respondents, which is 38%. Further in descending order of popularity are: “AOS” - 11 people, 22%; “Myth” - 7 people, 14%; SORTI - 7 people, 14%; “Drop” - 6 people, 12%.
2.2. Composition, properties and characteristics of the use of detergents.
To study the composition, properties, features of the use of dishwashing detergents, the labels of the products specified during the questioning of users were studied. As a rule, no one reads the instructions for washing dishes, but this does not relieve the manufacturer from the need to put this information on the label.
The research data are shown in table 1.
Table 1.
Composition, properties and characteristics of the use of detergents.
Fairy
AOS
MYTH
SORTI
A drop
Volume / ml
Price, rub.
Shelf life
18 months
18 months
18months
18 months
24 months
Composition
5-15% anionic and nonionic surfactants, fragrance, preservative, citroneplol, limonene and linalool.
5-15% anionic and nonionic surfactants, ethylenediaminetetraacetic acid salt, flavoring agents, preservatives
anionic and nonionic surfactants, sodium chloride, citric acid, preservative, perfume composition, citric acid
Water, anionic and nonionic surfactants, ethylenediaminetetraacetic acid salt, flavoring agents, preservatives,
Water, surfactant,
sodium chloride, citric acid, preservative, perfume composition, citric acid,
apply a small amount to a damp sponge
Drop a few drops on a damp sponge
Drop a few drops on a damp sponge
Apply a small amount to a damp sponge.
6. Precautions
In case of contact with eyes, rinse with water
Keep out of the reach of children.
Protect from sunlight. Keep away from heaters. Keep out of the reach of children. In case of contact with eyes, rinse with water.
Keep away from children, avoid contact with eyes.
These tables allow you to do the following findings:
With an equal amount of detergent, the price of the products is not the same.
The more expensive products include Fairy, AOS, the cheaper ones are Myth, SORTI and Drop.
The shelf life of all products is almost the same.
The main component of MS are surfactants.
in addition to surfactants, detergents contain dyes, preservatives, perfumes, but the labeling of these substances is not indicated, which does not allow us to conclude that they are safe for humans.
The exact amount of the product required for use is not indicated on the packages. It only says "apply a small amount on a sponge or on dishes" or "drip a few drops ...".
Almost all means, except "Fairy"Contain a warning:" Keep away from children "and describe the actions in case of contact with eyes.
Much attention is paid to the advertising label on the MS label: manufacturers indicate that all products effectively remove fat not only in hot but also in cold water, are easily washed off with water without leaving streaks. On the product label "Fairy"It is indicated that it complies with the RF standard for washability from dishes.
2.3. Physico - chemical properties of dishwashing detergents.
Experiment 1: Study of the pH of the solution.
One of the requirements for the use of dishwashing detergents is that they must have a neutral or slightly acidic pH of the solution (pH \u003d 5.5-7).
To determine the pH of the solution, we took a 0.1% solution of each agent, examined using an instrument for determining the pH of solutions. The results of the experiment are shown in table 2. Conclusion: All products are pH neutral.
Table 2:
Chemical properties of dishwashing detergents.
IndicatorFairy
Aoc
Myth
SORTI
A drop
1. pH of the solution
7,68
7,7
7,7
6,0
6,0
Content
phosphates
-
-
-
-
-
Experience 2 : The phosphate content of dishwashing detergents .
The presence of phosphate additives in detergents leads to a significant increase in the toxic properties of surfactants. They penetrate the microvasculature of the skin, are absorbed into the bloodstream and spread throughout the body. This leads to a change in the physicochemical properties of the blood itself and impaired immunity.
A 0.1% solution of each agent was tested with silver nitrate. The tubes did not have yellow or white precipitation. A yellow precipitate indicates the presence of phosphate ions (Ag 3 PO 4) in the samples; a white precipitate indicates the presence of chloride ion (AgCl) in the samples. The results of the experiment are shown in table 2.
Conclusion: No phosphate additives were found in detergents.
2.4. The influence of solutions of detergents for dishes on the course of processes
corrosion of iron objects.
During disposal, the used solutions of detergents for dishes are directly in contact with the metal pipes of the sewer, and when washing with metal dishes.
For the study, a 0.1% solution of each detergent was prepared and an iron nail 80 mm long was lowered into each. The experiment was carried out at room temperature. As a control sample, tap water was used. The experiment was carried out with triplicate.
On the first day, rust appeared on the nails in the following products: “AOS", "a drop SORTI". On the second day, a plaque of rust appeared in a test tube with tap water and on a nail dipped inFairy» . In the MIF tool, test tube rust appeared on the third day, while the nail remained clean. In the following days, the build-up of rust on the nails increased, moreover, the fastest means: “Fairy"," JSC S", "a drop SORTI". Rust was deposited at the bottom of the tubes — a brown precipitate. By the end of the observation, the height of the sediment was different in test tubes: “AOS"- 10mm," Fairy"-7mm," drop SORTI"- 9mm," MIF "- 4mm," Drop "-9mm, water - 3mm.
Conclusion: all tested solutions of detergents for dishes contribute to increased corrosion of iron objects, and therefore negatively affect sewer pipes and metal utensils.
Final part
Findings:
The most popular among the population are: Fairy,
« AOS. "
Detergent labels contain a large amount of promotional promises,
but not complete information on the composition and labeling of the ingredients, on the method of application.
All products are highly soluble in water.
4. All products are pH neutral.
5. The products do not contain harmful phosphate additives.
6. All tested solutions of detergents for dishes contribute to increased corrosion of iron objects, and therefore negatively affect sewer pipes and metal utensils.
We want to advise you, it is more responsible for the choice of detergents and not allow ads to fool themselves. Do not forget that our children and grandchildren will live on this planet, and we must take care of their future and health. Also, do not forget that our environment suffers from the use of certain detergents. We also want to advise you to handle detergents more carefully and not to forget that they contain components that can cause rashes, chemical burns, irritations and allergies. Always read the safety precautions written on the back of the packaging and keep detergents away from children.
We are aware that the use of detergents by people cannot be stopped, or even reduced. Moreover, with the increase in the population of our planet, the number and variety of detergents inevitably increase, which adversely affect not only humans, but also the environment.
We hope that in the course of progress safer detergents will be invented that will be able to completely dissolve in water without forming harmful chemical compounds. The information obtained during the research work can be used in teaching the school course in chemistry, biology, ecology, classroom hours, in conversations with students and parents, in elective classes in chemistry and ecology.
Literature:
1. Ambramzon A.A. and others. Surfactants. Synthesis, analysis, properties,
application. L., 1988.
2. Ashikhmina T.Ya. School environmental monitoring. Teaching aid / Ed. T.Ya. Ashihmina. - M .: Agar, 2000.
3.Bogdanov I.I. Conversations about the ecology: Textbook. allowance. - Omsk, 1995.
4. Spausus Z. Travel to the world of chemistry. M .: "Enlightenment", 1967.
Schwartz A., Peri D. Surfactants: their chemistry and technical applications. M., 1953.
Kharlampovich G.D. and others. Many-sided chemistry. - M .: "Education", 2004
Applications
Observation: 11/4/15
Observation: 11/10/15
