Chemistry educational projects. Research work in chemistry

Research students in chemistry

from the work experience of chemistry teacher Gabdrakhmanova T.V.

"MBOU Secondary School No. 5" Usinsk Komi Republic

Doubting, we begin to explore,

and by exploring, we find the truth.
Pierre Abelard

Introduction

One of the main functions of a teacher is to teach and develop the student's personality. The organization acquires special significance research activities, which has a significant impact on the personal and professional development of students.

For many years, I have been organizing research work among students in grades 8-11 in chemistry at our school.

Purposeresearch work is the education of an inquisitive student who actively explores the world, who masters the basics of the ability to learn, who knows how to listen and hear others.

Tasks:

develop the ability to design your activities (educational, research);

develop communication and Creative skills students;

improve skills in working with methods necessary for conducting research - observation, measurement, experiment;

draw up the results of the work, present your work at various competitions;

use students' experience to gain new knowledge;

developing the ability to independently work with various information.

Relevance of the research work:

search the greatest efficiency between innovation trends educational process And traditional technologies student learning;

the need to form a unique creative personality capable of thinking outside the box.

teaching students how to search, systematize and process information received through independent research activities.

Organization of research work in chemistry lessons

When organizing research work, theoretical training is necessary, which students receive in traditional classes for the primary consolidation of knowledge.

Students receive elements of research work in chemistry lessons, but various problems arise, since schoolchildren have a very vague idea of research methods, stages of work, and presentation of the results of their research work. It is difficult for them to select sources of information for a topic, generate ideas, find ways to solve problems, analyze, compare, make generalizations and conclusions, and correlate what has been achieved with previously set goals and objectives.When students are theoretically prepared, they should applyrockywith elements of research and research lessons. To stimulate interest in research activities in chemistry lessons, it is necessary to create a situation of success.

Lessons with elements of exploration.

Students practice in class individual teaching techniques that make up research activities. ToAsking students to conduct research requires forming their understanding of the subject and object of research, a hypothesis, and showing ways to test hypotheses. The research algorithm can be suggested to students using the example of a simple problem problem with chemical content. For example, “What properties should the oxide and hydroxide of an element with atomic number 13 have?” (Annex 1). After completing the work, students can be offered independent research on the problem: “What properties does hydroxide have? chemical element, if the electronic structure of the atom is expressed by the diagram: 2e; 8e; 5e? According to the content of the elements of research activity, various types of lessons are distinguished: lessons on choosing a topic and research method, working with sources of information, lessons on conducting an experiment, listening to reports, defending abstracts, etc.

The role of problem-based learning is very important in developing students' research skills. A problematic situation encourages students to engage in mental activity (analysis, synthesis, generalization, specification, etc.) When considering the topic “Corrosion of Metals,” a problematic situation can be created. The child gives a speech in which he talks about the dangers of corrosion. The speaker aims to give general idea about corrosion and the harm caused by this phenomenon. Lines from the report: “Corrosion causes not only direct damage (every year about one third of the metal produced per year throughout the world is lost from it), but also indirect: after all, they destroy metal constructions(cars, roofs, monuments, bridges).” We determine the problem that should be solved in the lesson: how to protect metals from corrosion? Students propose and justify methods for protecting metals from corrosion.

Chemical experiment is one of the ways to form and develop students’ research skills. An experiment in a lesson is used to create a problem situation, as well as as a means of confirming or refuting hypotheses put forward by students. When studying the topic “Hydrolysis of salts” at the beginning of the lesson, you can conduct a laboratory experiment and use universal indicator paper to determine the environment of salt solutions. Observations can be recorded in a table.

After conducting the experiment, together with the students we pose a problem. We consider salts as the result of a neutralization reaction. Why do salt solutions have different environments? Based on known knowledge about dissociation, students put forward various hypotheses. Students remember various signs of the classification of acids and bases, analyze the formulas of the proposed salts. During the conversation, students come to the conclusion that hydrolysis occurs, which is one of the chemical properties of salts.

Lesson Study

In the research lesson, students master the methodology of scientific research and establish the stages of scientific knowledge. Students master research knowledge and skills in stages, gradually increasing the degree of independence of students in their research educational activities.

In research lessons, various forms of student learning are used: individual, group, pair, collective. Preference is given to working in groups of 2-4 people, since working in a group contributes to the formation of communicative OUUN. To avoid the disadvantages of group work (conflicts, “hiding behind other people’s backs,” etc.), rules for group work are developed and used.

Workshop lesson

During practical lessons, students also work in groups. Each group consisting of 2-3 people receives an experimental task that must be completed during the lesson. When conducting a workshop for students, instructions are created that, according to certain rules, consistently establish the student’s actions.

Based on existing experience, we can propose the following structure of practical lessons:

Communication of the topic, purpose and objectives of the workshop;

Updating the basic knowledge and skills of students;

Motivation for students' learning activities;

Familiarization of students with instructions;

Selection of necessary didactic materials, training aids and equipment;

Carrying out student work under the guidance of the teacher;

Compilation of a report;

Discussion and theoretical interpretation of the obtained results.

This structure can be modified depending on the content of the work, the preparation of students and the availability of equipment. Workshops are conducted in the 11th grade, for example, on the topic “Obtaining, collecting and studying the properties of gases”, “Solving experimental problems in inorganic and organic chemistry”.

In teaching academic subjects, the main task is, first of all, to interest students in the process of cognition: to teach them to ask questions and try to find answers to them, to be able to explain the results, and to draw reasonable conclusions. The introduction of a research approach helps to strengthen the motivation of educational activities in teaching chemistry.

Research work at school can be varied. Students gain research skills in chemistry lessons practical work, which combine a variety of tasks: experimentaltasks, computational problems that require theoretical preparation for work, and reflect the main stages of research activity.

When solving experimental problems, students see the connection between chemistry and life, which contributes to the development of interest in studying the subject, and also prepares them for conscious performance of practical work (Appendix 2). Students' research activities are carried out both in chemistry lessons and outside of class time.

Research work outside of school hours+

- identification of talented and gifted students

Many students are capable of engaging in research, and even more so, research activities. It is important to be able to identify talented and capable students. It must be borne in mind that a student’s overall performance is not the main indicator of his real abilities. It is more difficult to identify students’ readiness for this species activities. Necessaryfind a student who is interested in this and who will complete the work.

In the classroom, such children are noticeable when performing practical and laboratory work, drafting projects, making presentations. When checking such tasks, it is necessary to pay attention to a creative approach to completing tasks and to the use of additional literature. When presenting such work, students are invited to discuss what they liked about this work and what else they can recommend. After the speech, it is proposed to answer several questions aimed at identifying attitudes towards this type of activity.

When analyzing such speeches, you need to pay attention to those students who show a stable interest in this type of work. In the future, these children can be invited to participate in research work.

- formation of interest in scientific creativity

Students do not always show interest in research work, so it is necessary to emphasize the student’s diligence and responsibility. How to interest a student? To do this, you can use several techniques. First, to convince that participation in research work will be useful in later life, outside of school. Secondly, knowing that teenagers strive to somehow stand out, to be different from the majority, then participation in research work will allow them to feel their special position among their classmates. Third, create an atmosphere of competition.

- work with literature

Any activity, whether a school essay or a doctoral dissertation, is impossible without working with literature sources. It is necessary to explain and show the student that a literary source is the basis of his work. During research work, students have to work with various sources information. The student’s task is to learn to work with the source, to acquire the skill independent work, correct design. It is necessary to give some recommendations when working with literary sources. Explain to students that not all the information collected may be necessary, and do not try to include all the collected material in the work.

- practical part of the work

During the practical part, students identify research problems, put forward hypotheses and test them, conducting theoretical or experimental research, and process the results obtained. The role of the teacher at this stage of organizing research activities is not dominant. The teacher cooperates with the student, advises, suggests how to work with the equipment correctly, and conduct an experiment..

Carrying out Scientific research, students acquire skills of independent creativity, independent acquisition of new knowledge, information and their practical application, which will be useful in any field of activity.

- speaking at scientific conferences

Scientific and practical conferences for students are held annually at the school. The success of a presentation at a scientific and practical conference depends on how well and confidently students can present their work in the section, prepare a computer presentation, and the text of the speech. It is necessary to clearly study the criteria for evaluating work. Defense of the work will be effective when the student is fluent in information, is familiar with all parts of the work performed, knows the terms, has public speaking skills, and is well prepared to speak at a conference. A student engaged in research exhibits significant independence at all stages of work. In such children, their cognitive activity increases and, as a rule, the quality of knowledge on the subject improves. Experience gained and research skills of studentsinfluence the quality of experiments in practical work: they quickly select reagents for carrying out reactions, make correct observations and conclusions. Research work can help students decide on a career choice where the main focus is working with chemicals.

Research work is time-consuming and mostly occurs outside of school hours. Students of 9-10th grades annuallyparticipate in a school scientific and practical conference, and present some works at a municipal scientific and practical conference. In 2016, 9b grade student Ekaterina Berestetskaya spoke at a city conference with the topic “Food additives and their effect on the human body”, the presentation was posted on the website https://sites.google.com/site/gabdrakhmanova5/home/vneklassnaa-rabota/gorodskaa-konferencia

In 2017, 9th grade students Artem Shcheglov with the topic “Adsorption properties of coal” and Denis Skvortsov with the topic “Iron - an element of civilization and life” spoke at the municipal scientific and practical conference and took third place. Appendix 3 presents fragments of the work of Artem Shcheglov. Link to presentations of works https://sites.google.com/site/gabdrakhmanova5/home/issledovatelskaa-rabota/zelezo

reagent

№ test tubes

litmus

NaOH

blue

NaCl

violet

HCl

red

Problem 2

Three numbered test tubes No. 1, No. 2, No. 3 contain solutions of barium chloride, sodium sulfate and potassium carbonate. Recognize substances, create reaction equations in molecular, full and reduced ionic form.

Work in pairs (filling out the table, drawing up reaction equations)

	reagents
Substance formulas	HCl	BaCl2	H2 SO4	№ test tubes
BaCl2			White sediment
Na2 SO4		White sediment
K2 CO3	Colorless and odorless gas

One of the substances reacts with the added reagent, but the other two do not. At the same time, we observe that in one of the test tubes the reaction actually took place, that is, some external sign of it should be observed - the release of gas, a change in color, the formation of a precipitate, etc.

Reaction equations

K2 CO3 +2 HCl → 2 KCl +H2 O+CO2

2 K+ +CO3 2- + 2H+ + 2 Cl- → 2 K+ + 2 Cl- +H2 O+CO2

2 H+ + CO3 2- →H2 O+CO2

Na2 SO4 + BaCl2 → BaSO4 ↓ + 2 NaCl

2 Na+ + SO4 2- + Ba2+ + 2 Cl- → BaSO4 ↓ + 2Na+ + 2 Cl-

Ba2+ + SO4 2- → BaSO4 ↓

H2 SO4 + BaCl2 → BaSO4 ↓ + 2 HCl

2H+ + SO4 2- + Ba2+ + 2 Cl- → BaSO4 ↓ + 2H+ + 2 Cl-

Ba2+ + SO4 2- → BaSO4 ↓

Problem 3

Three numbered test tubes contain solutions of sodium, magnesium, and aluminum chlorides. Recognize substances, create reaction equations in molecular, complete and abbreviated form.

Work in pairs (filling out the table, drawing up reaction equations).

Substance formulas

Reagents

№ test tubes

NaOH

Reaction equations

MgCl2 + 2 NaOH → Mg( OH) 2 ↓+ 2 NaCl

Mg2+ + 2 Cl- + 2 Na+ + 2 OH- → Mg( OH) 2 ↓ + 2 Na+ + 2 Cl-

Mg2+ + 2 OH- → Mg( OH) 2 ↓

AlCl3 + 3 NaOH → Al( OH) 3 ↓ + 3 NaCl

Al3+ +3 Cl- + 3Na+ + 3 OH- → Al(OH)3 ↓ + 3Na+ +3 Cl-

Al3+ +3 OH- → Al(OH)3 ↓

Al(OH)3 + NaOH → Na

Al(OH)3 +Na+ +OH- → Na+ + -

Appendix 3

(Fragments of work)

Research work in chemistry

"Adsorption properties of coal"

Completed by 9th grade student Artem Shcheglov

Introduction

In nature, the phenomenon of absorption of other substances by one substance, called sorption, is widespread. Bodies with a developed surface are capable of absorbing, i.e., adsorbing gas and liquid molecules from the surrounding volume. The practical significance of the phenomenon of adsorption in human life is very great. Let us at least remember the gas mask or household filters for water purification. Activated carbon is often used in life and in medicine as an adsorbent.

Relevance of the work :

attracting attention to the study of chemistry with practical side and applying the acquired knowledge in everyday life, developing interest in acquiring theoretical and practical skills in chemistry: working in the laboratory, working with the Internet to search and transmit information.

Purpose This work is to study and compare the adsorption capacity of white and black activated carbon.

Tasks set to achieve the goal :

find examples of the practical application of the adsorption capacity of activated carbon in human activity and life.

study the adsorption capacity of black and white activated carbon;

observe and analyze the phenomenon of adsorption using activated carbon as an example.

Learn how to use a variety of carbon-containing products without harm to health and what the capabilities of activated carbon are.

For research, I familiarized myself with various sources, technical literature, Internet resources, and found out that the phenomenon of adsorption is widely represented and a well-studied phenomenon. Adsorption underlies purification, drying, gas separation and other processes. Based on adsorption, water is purified and clarified, which is subsequently used for drinking and technical needs. In the theoretical part, I used materials from technical and historical literature, and for the experiment, I used the textbook for students Analytical Chemistry, Laboratory Workshop.

Research methods used in the work :

Study and selection of material;

Observationand analysis of adsorption phenomena;

Experiment.

Hypothesis

Despite high efficiency white coal, most people give their preference to a proven natural preparation - black activated carbon.Black activated carbon exhibits better adsorbing properties compared to white activated carbon.

Conclusion

Activated carbon demonstrated to us its adsorption abilities, i.e. absorbent properties.

Why is a small black tablet able to absorb various substances so effectively?

As I found out by studying literary sources, the point is in the special structure of carbon, which consists of layers of carbon atoms located randomly relative to each other, which is why space - pores - is formed between the layers. These pores give activated carbon its properties - the pores are able to absorb and retain other substances. There are an incredible number of such times. Thus, the pore area of just 1 gram of activated carbon can reach up to 2000 m2 ! White and black activated carbon is widely used based on its properties.

Conclusion s

Coal - medicine, you need to take it according to the instructions.

Black activated carbon is better known and more familiar to students than white.

White coal, despite its synthetic origin, is a higher quality adsorbent.

While studying the literature, I deepened my knowledge about the use of the adsorption capacity of activated carbon in human life. When comparing the adsorption capacity of white and black coal, I found that black coal absorbs odors better; discolors natural lingonberry syrup. White coal discolored litmus better.

Not all substances are completely adsorbed by activated carbon.

One of the reasons that these substances remained in solution and the color did not change may be that the sizes of the molecules of these substances are larger than the pore sizes of the adsorbent.

The hypothesis put forward was partially confirmed.

Stages of work: Review and analysis of labels on the products of several manufacturers of washing powders "Tide" "Tide" and "Dosia", "Dosia", studying the composition of shampoos "Head "Head & Shoulders", Shoulders", "Sebozol", baby cream, baby Johnsons baby oils according to their labels. Studying information on packaging; Watching commercials for “Tide”, “Tide” and “Dosia” washing powders. "Dosia". Assessing the credibility of advertising using experience from the perspective of chemistry; Compiling tables.

OBJECTIVES OF THE RESEARCH: I SET MYSELF THE TASK TO CHECK THE ACCURACY OF ADVERTISING WASHING POWDERS. THEN STUDY THE COMPOSITION OF WASHING POWDERS, BABY CREAM AND OIL, AND SHAMPOOS. Problem solving: To conduct the experiment, I chose advertising for TIDE and DOSIA washing powders, Johnsons baby cream and oil, Head & Shoulders and Sebozol shampoos.

ABOUT WRITING THE RESEARCH I SHOULD DO. Take "TIDE" and "DOSIA", "Head & Shoulders" and "Sebozol", baby cream and "Johnsons baby". Analyze the composition of each product. Take "TIDE" and "DOSIA", "Head & Shoulders" and "Sebozol" , baby cream and "Johnsons baby". analyze the composition of each product. Take fabrics stained with four types of stains and soak them in “TIDE” and “DOSIA”. Take fabrics stained with four types of stains and soak them in “TIDE” and “DOSIA”. Analyze the results obtained (assessed the degree of purity). Analyze the results obtained (assessed the degree of purity). The results of the study are presented in the table. The results of the study are presented in the table.

STAGE I. REVIEW AND ANALYSIS OF LABELS ON PRODUCTS. Review and analysis of labels on products from several manufacturers of washing powders "Tide" and "Dosia", studying the composition of shampoos "Head & Shoulders", "Sebozol", baby cream, baby oil "" according to their labels. Studying information on packaging. Review and analysis of labels on products from several manufacturers of washing powders “Tide” and “Dosia”, studying the composition of shampoos “Head & Shoulders”, “Sebozol”, baby cream, “Johnsons baby” baby oil according to their labels. Studying information on packaging.

Powder composition: “TIDE” “DOSIA” 15-30% - anionic surfactants 15-30% - anionic surfactants phosphates, phosphates, less than 5% - cationic surfactants less than 5% - cationic surfactants oxygen-containing bleach oxygen-containing bleach nonionic surfactants nonionic surfactants enzymes enzymes optical bleach optical brightener 5-15% anionic surfactants 15-30% water softening components oxygen-containing bleach less than 5% nonionic surfactant enzymes antifoaming agent flavoring

SHAMPOO CONTAINMENT: Water (H2O) Water (H2O) Ammonium lauryl sulfate (C12H29NO4S) Ammonium lauryl sulfate (C12H29NO4S) Sodium chloride (NaCl) Sodium chloride (NaCl) Glycol distearate Glycol distearate Zinc prithion Zinc prithion Perfume Perfume Sodium citrate (Na 3 C 6 H 5 O 7) Sodium citrate (Na 3 C 6 H 5 O 7) Citric acid (C 6 H 8 O 7) Citric acid (C 6 H 8 O 7) Benzyl alcohol (C 7 H 8 O) Benzyl alcohol ( C 7 H 8 O) Water (H2O) Water (H2O) Sodium laureth sulfate Sodium laureth sulfate Sodium chloride (NaCl) Sodium chloride (NaCl) Ketoconazal Ketoconazal Glycerin (C 3 H 5 (OH) 3) Glycerin (C 3 H 5 (OH) 3) “Head & Shoulders” “Sebozol”

OIL AND CREAM RESIDENCE: Vaseline oil Vaseline oil Isopropyl ether Isopropyl ether Aloe Barbadensis Aloe Barbadensis Vitamin E Vitamin E Perfume Perfume Glycerin (C 3 H 5 (OH) 3 Glycerin (C 3 H 5 (OH) 3 Oil Vaseline Oil Vaseline Oil extract calendula flowers Oil extract of calendula flowers Aloe vera gel Aloe vera gel CO2 extract CO2 chamomile extract Johnsons baby chamomile "Children's cream"

CONCLUSION: We do not deny the need for advertising and its important role in life modern man, but we urge you to be very thoughtful and critical of everything that advertising companies throw at us from the pages of newspapers, from TV screens, from numerous posters. leaflets and brochures. When reading any advertisement, try to find out whether its content contradicts the laws or concepts of natural sciences that we study at school.

Research

TOPIC: Dish detergents and their properties. The influence of detergents on metal corrosion.

Introduction page 2-3

Chapter 1. General information about dishwashing detergents pp. 4-5

1.1 Dishwashing detergents page 4

1.2 Composition of dishwashing detergents p. 4-5

Chapter 2. Diagnostics of dishwashing detergents pp. 6-8

2.1.Diagnostics of the use of dishwashing detergents p.6

2.2. Composition, properties and features of the use of detergents page 7

2.3. Physico-chemical properties of dishwashing detergents. pp. 7-8

2.4. Effect of dishwashing detergent solutions on page 8

the occurrence of corrosion processes of iron objects.

Conclusion page 9

References page 10

Appendix page 10

Introduction

The twenty-first century is a time when information has become the foundation on which all spheres rest human life. Therefore, every person must be sure that the information he has is reliable and will not bring him or those around him spiritual or physical harm. Streams of information reach us from everywhere, but the main source is the media. And often even an educated and experienced person cannot determine whether they are trying to deceive us by using advertising tricks or are just slightly exaggerating the merits of the goods or 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 simply promises “miracles.” Thanks to the active advertising policy of manufacturers, today almost every family uses special means. Thus, scientists have calculated 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 lives has not changed until now. MS is currently used to remove various types contaminants: stains on clothes, rust, dirty dishes, etc.

In their composition, dishwashing detergents are close to shampoos and shower gels. That is, to hygiene products. And they are subject to special safety requirements. This is all good, however, dishwashing detergents are listed as household chemicals. This means that they do not need a hygienic certificate guaranteeing safety. The requirements for toilet bowl cleaners and dishes are the same. Manufacturers can subject their products to safety tests, but voluntarily. Chemists admit: this certificate only guarantees that at the time of use you will not be poisoned or damage the skin of your hands. But what happens over time in the body, which is constantly exposed to detergent residues, has not been studied.

With the constant increase in the number of new chemicals entering circulation, actual problem is to study them in order to obtain information about the potential danger of substances and develop preventive measures to prevent adverse effects on the human body and the environment. Among the complex of environmental factors subject to hygienic control, household chemical products (CHGs) deserve much attention due to their mass production and use, the variety of components included in the formulations, as well as their possible direct effect on the human body. As you know, after use, all chemicals end up in the environment and have a detrimental effect on it, but we don’t think about it. Therefore, we decided to devote our work specifically to household chemicals and, having studied the composition of MS for dishes, determine how safe their use is.

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 caused to us by MS, we first need to learn more about them than is advertised. We decided to conduct a study in our school to identify the tools that use most in demand, and analyze what justified the choice of participants in our study. It’s up to each person to say yes or no to MS, but if you follow certain rules, the health risk will be minimal.

Practical significance The work is that the information obtained from the results of research work 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 increased corrosion of metals from which plumbing fixtures are made.

Target works: to study the physical and chemical properties of detergents, to study the effect of detergents on the corrosion of metals from which plumbing fixtures are made.

Tasks :

1. Study the literature on this issue;

2. Identify the brands of dishwashing detergents most commonly used at home;

3. Study the composition and data of dishwashing detergents using their labels.

4. Investigate the physicochemical properties of detergents;

5. Consider the effect of detergents on metal objects (nails).

Object of study : liquid dishwashing detergents.

Subject of study: properties and safety of using dishwashing detergents, metal corrosion.

Hypothesis: if you have complete information about the composition and properties of detergents, thenYou can preserve human health and prevent damage to plumbing fixtures made of iron.

In accordance with the objectives of the study, systematization methods were used theoretical material, research methods and observation methods, generalization of accumulated material.

Chapter 1. General information about dishwashing detergents

1.1 Dishwashing detergents and their properties

Special dishes detergents first appeared in the 1950s. Means for hand wash The dishes are available in liquid or gel form. Gel products are considered more effective than liquid products.

The main properties of the product is its cleaning ability. A big plus of the product is its ability to effectively cope with oil and grease stains in cold water, this is achieved through the selection of the optimal surfactant composition.

Another important property of hand dishwashing detergent is its gentle effect on the skin of the hands. It is worth noting that manufacturers' statements that the pH level of their products is 5.5 cannot in any case guarantee the absence of irritation, especially for people prone to allergies. Therefore, your skin needs protection while washing dishes. The product must contain softening components and do not forget that your hands can be protected from harmful effects products using ordinary rubber gloves.

Its composition can tell a lot about a dishwashing detergent.

1.2 Composition dishwashing liquid

The basis of the detergent is surfactants (surfactants). They are the ones who determine its cleaning ability.

Surfactants are divided into two types: ionic and non-ionic (non-ionic).

The fundamental difference is that nonionic surfactants are not subject to electrolytic dissociation, i.e. they do not disintegrate 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 ions are positively charged. Some surfactants, depending on the conditions under which they are used, exhibit either anionic or cationic properties, which is why they are called amphoteric or ampholytic. Anionic surfactants are organic acids and their salts. Cationic - bases, usually amines, and their salts. The majority of global surfactant production is anionic.

Synthetic detergents necessarily contain a number of auxiliary substances that improve their cleaning 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), salts of peroxide acids with bleaching and disinfecting properties (sodium perborate and percarbonates). Exactly these chemical substances and enter into chemical reactions With the metals from which plumbing fixtures are made, corrosion of the metals occurs under the influence of these substances. Corrosion causes billions of dollars in losses every year, and resolving this problem is an important task. The main damage caused by corrosion is not the loss of metal as such, but the enormous cost of the products destroyed by corrosion. That is why the annual losses from it in industry developed countries so great.

An important role is played by the organic components of surfactants: carboxymethylcellulose, which prevents the re-deposition of contaminants from the washing solution onto the washed surface, and the so-called hydrotropes, which increase the solubility and accelerate the dissolution of surfactants in water.

Some detergents contain enzymes that remove insoluble protein contaminants, organic bactericides, and foam stabilizers.

Many detergents add aromatic substances (fragrances) to eliminate unpleasant odors and give the washed surface a fresh aroma. True, the smell of apple, lemon or, for example, forest berries does not mean the presence of extracts of the above-mentioned fruits in this product.

Also, dishwashing detergents may contain substances that soften the negative effects on the skin of the hands. The most common additives are glycerin, silicone and plant extracts. Glycerin and silicone have a similar effect; they create protective film preventing it from drying out. At the same time, the surface film created by silicone can protect against the penetration of substances harmful to the skin contained in the detergent.

Plant extracts soften the skin, have a calming effect, and relieve irritation that can be caused by individual components of surfactants (for example, aloe vera milk has this effect). But even with everyone undoubted advantages These additives cannot guarantee complete safety for your skin.

Chapter 2. Diagnostics of dishwashing detergents

In order to find out which of the tools are the most used, we interviewed students, teachers and school staff. 50 people took part in the survey.

Survey data shows that the most popular remedy is "Fairy". It is used by 19 people from the respondents, which is 38%. Next in descending order of popularity are: “AOC” - 11 people, 22%; “Myth” - 7 people, 14%; "SORTI" - 7 people, 14%; “Drop” - 6 people, 12%.

2.2. Composition, properties and features of the use of detergents.

To study the composition, properties, and features of the use of dishwashing detergents, the labels of the products indicated during the user survey were studied. As a rule, no one reads dishwashing instructions, but this does not relieve the manufacturer from the need to put this information on the label.

The study data are shown in Table 1.

Table 1.

Composition, properties and features of the use of detergents.

Fairy

AOC

MYTH

SORTI

A drop

Volume/ml

Price, rub.

Best before date

18 months

24 months

Compound

5-15% anionic and nonionic surfactants, fragrance, preservative, citroneplol, limonene and linalool.

5-15% anionic and nonionic surfactants, ethylenediaminetetraacetic acid salt, flavoring additives, preservatives

anionic and nonionic surfactants, sodium chloride, lemon acid, preservative, perfume composition, citric acid

Water, anionic and nonionic surfactants, ethylenediaminetetraacetic acid salt, flavoring additives, preservatives,

Water, surfactant,

sodium chloride, citric acid, preservative, perfume composition, citric acid,

Apply a small amount to a damp sponge

Place a few drops of product on a damp sponge

Apply a small amount of product to a damp sponge

6. Precautions

In case of contact with eyes, rinse with water

Keep away from children

Protect from sunlight. Keep away from heating devices. Keep away from 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: conclusions:

With the same volume of detergent, the price of the products is not the same.

More expensive products include “Fairy”, “AOC”, cheaper products are “Myth”, “SORTI” and “Kaplya”.

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, and perfume compositions, but the labeling of these substances is not indicated, which does not allow us to draw a conclusion about their safety for humans.

The packages do not indicate the exact amount of product required for use. It just says “apply a small amount to a sponge or on dishes” or “drop a few drops...”.

Almost all means, except "Fairy» contain the warning: “Keep away from children” and describe what to do if the product gets into your eyes.

Much attention is paid to advertising data on the MS label: manufacturers indicate that all products effectively remove fat not only in hot but also in cold water, and are easily washed off with water without leaving streaks. On the product label "Fairy» it is indicated that it complies with the Russian 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 value of the solution (pH = 5.5-7).

To determine the pH of the solution, we took a 0.1% solution of each product and examined it using a device 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 dishwashing detergents.

Index

Fairy

AOC

Myth

SORTI

A drop

1. pH of the solution

7,68

7,7

6,0

Content

phosphates

Experience 2 : Phosphate content in dishwashing detergents .

The presence of phosphate additives in detergents leads to a significant increase in the toxic properties of surfactants. They penetrate the microvessels of the skin, are absorbed into the blood and spread throughout the body. This leads to change physical and chemical properties blood itself and impaired immunity.

A 0.1% solution of each product was tested with silver nitrate. There was no yellow or white precipitate in the tubes. A yellow precipitate indicates the presence of phosphate ions (Ag 3 PO 4) in the samples, a white precipitate indicates the presence of chloride ions (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 dishwashing detergent solutions on processes

corrosion of iron objects.

When disposed of, used dishwashing detergent solutions come into direct contact with metal pipes sewer, and when washing with metal utensils.

For the study, a 0.1% solution of each detergent was prepared and an 80 mm long iron nail was lowered into each. The experiment was carried out at room temperature. Used as a control sample tap water. The experiment was carried out with three repetitions.

On the first day, rust appeared on the nails in the following products: “AOS", "a drop SORTI" On the second day, a coating of rust appeared in a test tube with tap water and on a nail dipped in “Fairy» . In the “MYTH” product, rust appeared in a test tube on the third day, while the nail remained clean. In the following days, the rust coating on the nails increased, and most quickly in the media: “Fairy", "JSC S", "a drop SORTI" Rust was deposited at the bottom of the test tubes - a brown sediment. By the end of the observation, the height of the sediment was different in the test tubes: “AOS" - 10mm, " Fairy"-7mm, "drop SORTI"- 9mm, "MYTH" - 4mm, "Drop" - 9mm, water - 3mm.

Conclusion: All studied solutions of dishwashing detergents contribute to increased corrosion of iron objects, and therefore have a negative effect on sewer pipes and metal utensils.

Final part

Conclusions:

The most popular products among the population are: “Fairy”,

« A.O.S."

Detergent labels contain a large amount of advertising promises,

but not full information about the composition and labeling of ingredients, about 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 dishwashing detergents contribute to increased corrosion of iron objects, and therefore have a negative effect on sewer pipes and metal utensils.

We would like to advise you to be more responsible when choosing detergents and not to let advertisements deceive you. 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 health suffers from the use of certain detergents. environment. We also want to advise you to be careful when handling detergents and not to forget that they contain components that can cause rashes, chemical burns, irritation and allergies. Always read the safety precautions on the back of the package and keep cleaning products away from children.

We are aware that human consumption of detergents cannot be stopped, or even reduced. Moreover, with the increase in the population of our planet, the quantity and variety of detergents inevitably increases, which have a detrimental effect not only on humans, but also on the environment.

We hope that as progress progresses, safer detergents will be invented that will be able to completely dissolve in water without forming harmful chemical compounds. The information obtained during research work can be used when teaching school courses in chemistry, biology, ecology, classroom hours, during 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. Educational and methodological manual / Ed. T.Ya. Ashikhmina. – M.: Agar, 2000.

3. Bogdanov I.I. Conversations about ecology: Textbook. allowance. – Omsk, 1995.

4. Shpausus Z. Journey into 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 faces of chemistry. – M.: “Enlightenment”, 2004

Applications

Observation:4.11.15

Observation:10.11.15