Main rules of life What is life safety at school? Program and study of life safety at school

To use presentation previews, create an account for yourself ( account) Google and log in: https://accounts.google.com

Slide captions:

Characteristics of a chemical element by its position in periodic table elements of D.I. Mendeleev.

I. Position of the element in the periodic table: serial number of the element; period number; group number, subgroup; relative atomic mass. II. Atomic structure of an element: charge of the nucleus of an atom; atomic composition formula (amount p + ; n 0 ; e -); the number of energy levels and the placement of electrons on them; electronic configuration of an atom; valence possibilities of an atom.

III. Formulas of compounds, chemical nature, its proof metal, non-metal, transition element; formula of the higher oxide and its character; the formula of the corresponding hydroxide and its character; formula of a volatile hydrogen compound. IV. Comparison with neighbors: by period; by subgroup. (metals cannot be compared with non-metals)

Characteristics of Phosphorus by its position in PSHE Position in PSHE: No. 15; Period No. 3; Group No. V, main subgroup; Ar (P) = 31. Atomic structure: Z i (P) = + 15; (p + = 15; n 0 = 16) e - = 15 +15) 2) 8) 5 1s 2 2s 2 2p 6 3s 2 3p 3 −3; 0; +3; +5 Compounds... Non-metal P 2 O 5 – acidic; P 2 O 5 + NaOH = H 3 PO 4 – phosphoric acid; H 3 PO 4 + NaOH = PH 3 – phosphine Comparison... Si P > As

Homework § 1, exercises 3,4 (part 1), independently characterize sodium.

Independent work According to the above plan, characterize the following elements: option: No. 19 (potassium); option: No. 17 (chlorine); option: No. 13 (aluminum) Homework: §1, give characteristics No. 14, 20.

On the topic: methodological developments, presentations and notes

Characteristics of an element by its position in the PSHE.

The work was done in the form of a presentation. If desired, you can insert video clips on the acid-base properties of oxides and hydroxides of elements....

Characteristics of an element by position in the Periodic Table

The work contains: - presentation for the lesson (theory); - presentation of test work. For 8th grade....

System-activity approach to the study of chemistry. Grade 9 Characteristics of an element by its position in the periodic table.

A description is given of the first lesson of 9th grade in chemistry on the topic "Characteristics of an element by its position in the periodic table." The lesson is given using a system-activity approach, using various...

Plan for the characteristics of a chemical element-metal based on its position in the PSHE D.I. Mendeleev.

9th grade chemistry lesson notes. Lesson type: lesson of generalization and systematization of acquired knowledge. ...

presentation for a chemistry lesson "Characteristics of a nonmetal chemical element by position in Mendeleev's PSHE"

The presentation gives a plan general characteristics chem. element according to its position in the PSHE. Review the structure of the atom, types of chemicals. connections, classification Not organic matter and their properties in the light...

Carbon (C)– typical non-metal; in the periodic table it is in the 2nd period of group IV, the main subgroup. Serial number 6, Ar = 12.011 amu, nuclear charge +6.

Physical properties: carbon forms many allotropic modifications: diamond- one of the hardest substances graphite, coal, soot.

A carbon atom has 6 electrons: 1s 2 2s 2 2p 2 . The last two electrons are located in separate p-orbitals and are unpaired. In principle, this pair could occupy the same orbital, but in this case the interelectron repulsion greatly increases. For this reason, one of them takes 2p x, and the other, either 2p y , or 2p z orbitals.

The difference in the energy of the s- and p-sublevels of the outer layer is small, so the atom quite easily goes into an excited state, in which one of the two electrons from the 2s orbital passes to a free one 2 rub. A valence state appears with the configuration 1s 2 2s 1 2p x 1 2p y 1 2p z 1 . It is this state of the carbon atom that is characteristic of the diamond lattice—tetrahedral spatial arrangement of hybrid orbitals, identical length and energy of bonds.

This phenomenon is known to be called sp 3 -hybridization, and the emerging functions are sp 3 -hybrid . The formation of four sp 3 bonds provides the carbon atom with a more stable state than three r-r- and one s-s-connection. In addition to sp 3 hybridization, sp 2 and sp hybridization is also observed at the carbon atom . In the first case, mutual overlap occurs s- and two p-orbitals. Three equivalent sp 2 hybrid orbitals are formed, located in the same plane at an angle of 120° to each other. The third orbital p is unchanged and directed perpendicular to the plane sp2.

During sp hybridization, the s and p orbitals overlap. An angle of 180° arises between the two equivalent hybrid orbitals that are formed, while the two p-orbitals of each atom remain unchanged.

Allotropy of carbon. Diamond and graphite

In a graphite crystal, carbon atoms are located in parallel planes, occupying the vertices of regular hexagons. Each carbon atom is connected to three neighboring sp 2 hybrid bonds. The connection between parallel planes is carried out due to van der Waals forces. The free p-orbitals of each atom are directed perpendicular to the planes of covalent bonds. Their overlap explains the additional π bond between the carbon atoms. Thus, from the valence state in which the carbon atoms in a substance are located determines the properties of this substance.

Chemical properties of carbon

The most characteristic oxidation states are: +4, +2.

At low temperatures carbon is inert, but when heated its activity increases.

Carbon as a reducing agent:

- with oxygen
C 0 + O 2 – t° = CO 2 carbon dioxide
with a lack of oxygen - incomplete combustion:
2C 0 + O 2 – t° = 2C +2 O carbon monoxide

- with fluorine
C + 2F 2 = CF 4

- with water vapor
C 0 + H 2 O – 1200° = C +2 O + H 2 water gas

- with metal oxides. This is how metal is smelted from ore.
C 0 + 2CuO – t° = 2Cu + C +4 O 2

- with acids - oxidizing agents:
C 0 + 2H 2 SO 4 (conc.) = C +4 O 2 + 2SO 2 + 2H 2 O
C 0 + 4HNO 3 (conc.) = C +4 O 2 + 4NO 2 + 2H 2 O

- forms carbon disulfide with sulfur:
C + 2S 2 = CS 2.

Carbon as an oxidizing agent:

- forms carbides with some metals

4Al + 3C 0 = Al 4 C 3

Ca + 2C 0 = CaC 2 -4

- with hydrogen - methane (as well as a huge amount organic compounds)

C0 + 2H2 = CH4

— with silicon, forms carborundum (at 2000 °C in an electric furnace):

Finding carbon in nature

Free carbon occurs in the form of diamond and graphite. In the form of compounds, carbon is found in minerals: chalk, marble, limestone - CaCO 3, dolomite - MgCO 3 *CaCO 3; hydrocarbonates - Mg(HCO 3) 2 and Ca(HCO 3) 2, CO 2 is part of the air; carbon is the main integral part natural organic compounds - gas, oil, coal, peat, is part of organic substances, proteins, fats, carbohydrates, amino acids that make up living organisms.

Inorganic carbon compounds

Neither C 4+ nor C 4- ions are formed during any ordinary chemical processes: carbon compounds contain covalent bonds different polarity.

Carbon monoxide CO

Carbon monoxide; colorless, odorless, slightly soluble in water, soluble in organic solvents, toxic, boiling point = -192°C; t pl. = -205°C.

Receipt
1) In industry (in gas generators):
C + O 2 = CO 2

2) In the laboratory - thermal decomposition of formic or oxalic acid in the presence of H 2 SO 4 (conc.):
HCOOH = H2O + CO

H 2 C 2 O 4 = CO + CO 2 + H 2 O

Chemical properties

Under normal conditions, CO is inert; when heated - a reducing agent; non-salt-forming oxide.

1) with oxygen

2C +2 O + O 2 = 2C +4 O 2

2) with metal oxides

C +2 O + CuO = Cu + C +4 O 2

3) with chlorine (in the light)

CO + Cl 2 – hn = COCl 2 (phosgene)

4) reacts with alkali melts (under pressure)

CO + NaOH = HCOONa (sodium formate)

5) forms carbonyls with transition metals

Ni + 4CO – t° = Ni(CO) 4

Fe + 5CO – t° = Fe(CO) 5

Carbon monoxide (IV) CO2

Carbon dioxide, colorless, odorless, solubility in water - 0.9V CO 2 dissolves in 1V H 2 O (at normal conditions); heavier than air; t°pl. = -78.5°C (solid CO 2 is called “dry ice”); does not support combustion.

Receipt

Thermal decomposition of carbonic acid salts (carbonates). Limestone firing:

CaCO 3 – t° = CaO + CO 2

The action of strong acids on carbonates and bicarbonates:

CaCO 3 + 2HCl = CaCl 2 + H 2 O + CO 2

NaHCO 3 + HCl = NaCl + H 2 O + CO 2

ChemicalpropertiesCO2
Acidic oxide: reacts with basic oxides and bases, forming carbonic acid salts

Na 2 O + CO 2 = Na 2 CO 3

2NaOH + CO 2 = Na 2 CO 3 + H 2 O

NaOH + CO 2 = NaHCO 3

At elevated temperature may exhibit oxidizing properties

C +4 O 2 + 2Mg – t° = 2Mg +2 O + C 0

Qualitative reaction

Cloudiness of lime water:

Ca(OH) 2 + CO 2 = CaCO 3 ¯ (white precipitate) + H 2 O

It disappears when CO 2 is passed through lime water for a long time, because insoluble calcium carbonate turns into soluble bicarbonate:

CaCO 3 + H 2 O + CO 2 = Ca(HCO 3) 2

Carbonic acid and itssalt

H 2CO 3 - A weak acid, it exists only in aqueous solution:

CO 2 + H 2 O ↔ H 2 CO 3

Dibasic:
H 2 CO 3 ↔ H + + HCO 3 - Acid salts - bicarbonates, bicarbonates
HCO 3 - ↔ H + + CO 3 2- Medium salts - carbonates

All properties of acids are characteristic.

Carbonates and bicarbonates can transform into each other:

2NaHCO 3 – t° = Na 2 CO 3 + H 2 O + CO 2

Na 2 CO 3 + H 2 O + CO 2 = 2NaHCO 3

Metal carbonates (except alkali metals) decarboxylate when heated to form an oxide:

CuCO 3 – t° = CuO + CO 2

Qualitative reaction- “boiling” under the influence of a strong acid:

Na 2 CO 3 + 2HCl = 2NaCl + H 2 O + CO 2

CO 3 2- + 2H + = H 2 O + CO 2

Carbides

Calcium carbide:

CaO + 3 C = CaC 2 + CO

CaC 2 + 2 H 2 O = Ca(OH) 2 + C 2 H 2.

Acetylene is released when zinc, cadmium, lanthanum and cerium carbides react with water:

2 LaC 2 + 6 H 2 O = 2La(OH) 3 + 2 C 2 H 2 + H 2.

Be 2 C and Al 4 C 3 decompose with water to form methane:

Al 4 C 3 + 12 H 2 O = 4 Al(OH) 3 = 3 CH 4.

In technology, titanium carbides TiC, tungsten W 2 C (hard alloys), silicon SiC (carborundum - as an abrasive and material for heaters) are used.

Cyanide

obtained by heating soda in an atmosphere of ammonia and carbon monoxide:

Na 2 CO 3 + 2 NH 3 + 3 CO = 2 NaCN + 2 H 2 O + H 2 + 2 CO 2

Hydrocyanic acid HCN is an important product chemical industry, is widely used in organic synthesis. Its global production reaches 200 thousand tons per year. Electronic structure cyanide anion is similar to carbon monoxide (II), such particles are called isoelectronic:

C = O: [:C = N:] –

Cyanides (0.1-0.2% aqueous solution) are used in gold mining:

2 Au + 4 KCN + H 2 O + 0.5 O 2 = 2 K + 2 KOH.

When boiling solutions of cyanide with sulfur or melting solids, they form thiocyanates:
KCN + S = KSCN.

When cyanides of low-active metals are heated, cyanide is obtained: Hg(CN) 2 = Hg + (CN) 2. Cyanide solutions are oxidized to cyanates:

2 KCN + O 2 = 2 KOCN.

Cyanic acid exists in two forms:

H-N=C=O; H-O-C = N:

In 1828, Friedrich Wöhler (1800-1882) obtained urea from ammonium cyanate: NH 4 OCN = CO(NH 2) 2 by evaporating an aqueous solution.

This event is usually regarded as the victory of synthetic chemistry over "vitalistic theory".

There is an isomer of cyanic acid - explosive acid

H-O-N=C.
Its salts (mercuric fulminate Hg(ONC) 2) are used in impact igniters.

Synthesis urea(urea):

CO 2 + 2 NH 3 = CO(NH 2) 2 + H 2 O. At 130 0 C and 100 atm.

Urea is a carbonic acid amide; there is also its “nitrogen analogue” – guanidine.

Carbonates

The most important inorganic carbon compounds are salts of carbonic acid (carbonates). H 2 CO 3 is a weak acid (K 1 = 1.3 10 -4; K 2 = 5 10 -11). Carbonate buffer supports carbon dioxide balance in the atmosphere. The world's oceans have enormous buffer capacity because they are an open system. The main buffer reaction is the equilibrium during the dissociation of carbonic acid:

H 2 CO 3 ↔ H + + HCO 3 - .

When acidity decreases, additional absorption of carbon dioxide from the atmosphere occurs with the formation of acid:
CO 2 + H 2 O ↔ H 2 CO 3 .

As acidity increases, carbonate rocks (shells, chalk and limestone sediments in the ocean) dissolve; this compensates for the loss of hydrocarbonate ions:

H + + CO 3 2- ↔ HCO 3 —

CaCO 3 (solid) ↔ Ca 2+ + CO 3 2-

Solid carbonates turn into soluble bicarbonates. It is this process of chemically dissolving excess carbon dioxide that counteracts " greenhouse effect» – global warming due to absorption carbon dioxide thermal radiation of the Earth. About a third of the world's production of soda (sodium carbonate Na 2 CO 3) is used in glass production.

Lesson objectives: development and strengthening of knowledge about the basics of life safety acquired in primary school; consolidation of the rules of life safety studied in the first quarter; presentation of “Fifth-grader Diplomas”.

Tasks: repeat dangerous life situations with children; how to protect yourself from dangers; consolidate knowledge about the rules traffic and rules for handling electrical appliances; consider fire hazardous situations.

Equipment: textbooks, computer, projector, tables, “Diplomas for fifth graders.”

DURING THE CLASSES

1. Organizing time

- Hello! Guys, we have already managed to make friends and get to know each other. I am very pleased with our mutual cooperation. Today we have a general lesson where we will summarize the results of the first quarter of teaching the basics of life safety in the fifth grade and repeat the main rules of life safety.

2. You are fifth graders. Every day brings you new knowledge, interesting things, various situations, which may upset us. And you and I have already considered many of them, when we need to demonstrate the necessary knowledge and promptly recognize, avoid, contain and reduce dangers. By discussing cautionary tales, we take the first steps towards preventing and overcoming dangers. We find the causes of troubles and make recommendations for safe behavior.

– I am your guide to all the rules of the basics of BJ. I will be glad to advise you, help you, and study all kinds of situations. And, therefore, always contact me for advice and any questions. You can also contact older comrades and parents. Everyone around you will meet you halfway and help you. After all, when we are armed with certain knowledge, we contribute to the formation of our environment according to all safety rules.

3. Before we start reviewing some of the questions we have studied during this period, I would like to present you with the 5th Grade Diplomas.
Here I have noted special moments from my observations of your actions in and outside of class. I came up with my own disciplines that did not exist at school, printed them out and collected them in a book. And I hope that you will save them, and from time to time you will remember these disciplines and reflect on your actions. Although I presented these disciplines in the form of joke names, they have a deep meaning. semantic meaning, which will help you in various actions.

Life safety – protection of our lives! And to begin with, I will ask you to read short poems about life safety. Children read poetry.

If suddenly a fire breaks out,
You immediately collapsed from fear.
Remember our life safety,
And consider yourself saved!

I was swinging on a swing
And she hurt her leg.
“Give me help immediately!”
I shout to Seryozhka.

4. Presentation of “diplomas”

(The following is the content of this material.) Congratulations and wishes.

A real fifth-grader diploma

FULL NAME
Municipal educational institution secondary school No.

2011-2012 y/y.

In a short time probation from 01.09.2011 to 25.10.2011 passed full course preparation
to study in the fifth grade and studied the “ABC of Life Safety with the main rules of Life Safety.”

By the end of the first quarter, he has the following indicators in the following disciplines:

What does life safety teach!?
Familiarization with the life safety room
Obstacle running in the classroom
Amateur course on the topic: “Fight in the corridor, everything is in smoke, nothing is visible”
Development of thunderous speech
The ability to keep your mouth shut when asked to answer
Course on familiarization with the nature of the school yard: “No matter the bush, there is no leaf”
Curiosity is not a vice, but a method of learning “Why”
Learning by playing
A moment of rest
ABC of life safety
Composition fantastic stories, tall tales and puzzles
Coming up with new concepts, how to “increase”
A gas mask is a means of protection in the classroom when the teacher is absent
Invent and find dangers for yourself at home and on the street
Traffic rules. Whoever pushed harder with his shoulder went to the main...

– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)
– 5 (Great)

Completed a full elective course using the “Give back to the offender if the teacher is not looking” method
if he’s watching, know how to shed a tear in time” to “excellent.”
By decision of the special commission of secondary school No., this student is recommended
continuation of further study of the life safety course at school.

Teacher -
Director -
Head teacher –
Printing op-amp

5. Friends, remember. Any business has its own procedures, rules of action.
While driving on the road, everyone follows strict laws with numerous warning signs. We will repeat the traffic rules and watch the slide film “Traffic Safety”.

Questions and answers for this section. Active discussion.

6. Demonstration of a presentation on traffic rules

7. Show table with traffic signs

A student reads a poem about traffic rules that we taught in the last lesson.

The city in which you and I live,
It can rightly be compared to an ABC book.
ABC of streets, avenues, roads
The city gives us a lesson all the time.

Here it is, the alphabet, above your head:
Signs are posted along the pavement.
Always remember the ABC of roads,
So that no trouble happens to you.

8. Dangerous situations. What are they? Where are they?
Let's try to outline the space in which we live.

(All places are listed - bathroom, kitchen, balcony, store, school, bus, theater, etc.)

Wherever we go, wherever we live, dangers can await us. And we remember various unfavorable factors and conditions. Also, our actions in dangerous situations. The work is carried out in the form of a conversation and question-answer. At the request of the students, 2-3 situations are considered.

9. Fires. Fighting fires and protecting life during a fire.

The teacher reads an excerpt from S. Marshak’s poem “Cat’s House.” Conclusions are drawn about fire safety and actions during a fire.

Tili-tili,
Tili-tili,
Tili-tili, tili-bom!
The cat's house is on fire!
The cat's house caught fire
A chicken is running with a bucket,
And behind her with all his might
A rooster runs with a broom.
Piglet - with sieve
And a goat with a lantern.
Tili-bom!
Tili-bom!

Rooks:

Hey fire brigade
We must hurry!
Harness ten pairs.
Let's go, let's go to the fire.
Hurry, without delay,
Pour water into barrels.
Tili-tili-tili-bom!
The cat's house is on fire!
Stop, pig! Wait, goat!
Why are you staring?
Carry water in buckets.

Man has long learned to use the “red flower”, i.e. fire. But whenever a person forgets about caution, a peaceful fire turns into an uncontrollable flame of fire. Fires are scary not only because of fire, but also because of its companions:

1) toxic smoke;
2) high temperature;
3) poor visibility;
4) panic and confusion;
5) breakage of electrical wires and the possibility of electric shock;
6) collapse of structures.

Let's now point out the reasons that led to the fire in the Cat's house. A short discussion of fire and its “companions.”
Consider the following situation: “On a hot July night, a resident of the Moscow district of Cherpanovo noticed a small glow near the garages, similar to the light of a car’s headlights. But this glow was weaker and lower, which attracted attention. Using binoculars, he managed to notice a small stream of smoke. Arriving firefighters found that oily rags and oil cans had caught fire in the garage due to the heat. Thus, the vigilance of a Muscovite prevented a large fire in the courtyard of a residential building.
Guys, let’s evaluate this person’s actions in small phrases.

Brief discussion.

10. Summing up our work today, I want to Once again emphasize that dangerous situations can and should be anticipated, provided that we comply with all the safety rules that we are studying and still need to study. After all, in every dangerous situation There must be an obvious or hidden reason for its occurrence, which is the result of incorrect human actions. Therefore, I will once again ask you to repeat and remember all the rules that we are talking about: rules of conduct at home, in in public places, in transport, on the street, in bodies of water, rules for using electrical appliances and many others.

11. The board is displayed through a projector: “Our future is in our hands! Our actions are our rules! Follow the rules of life safety!

12. Thank you for a wonderful hour. See you!

04.05.2013 21:33

Newsline

20:02
19:02
14:53
14:02
19:42
18:32
16:32

The purpose of the lesson: introduce students to the rules of behavior in situations of a criminal nature

Visual complex:

Items: handbag, umbrella, can of hairspray, whistle.
Application: PowerPoint presentations.

During the classes

1. Organizational moment.

Teacher: Modern life is full of surprises, sometimes often dangerous and unpleasant. There are often cases when at a distant transport stop, in a dark entrance, in a quiet park, in the vestibule of an electric train, various kinds crimes.

Not everything, of course, depends on us. If we stick to some elementary rules. Let's behave more carefully. Then the likelihood of protecting your life, health, and dignity from criminal attacks will increase significantly.

2. Studying a new topic.

Teacher: How do you understand what a crime situation is?

Students lead a discussion. During the discussion, they formulate a definition and take notes (TO).

TO: A criminogenic situation is a situation when a person finds himself in conditions where a crime occurs or this situation leads to the occurrence of a crime.

Teacher: What should be done in crime situations?

Students: The most important thing is not to become a victim of a crime and a source of crime. Presentation 1.

The teacher suggests considering specific situations under conventional names.

How to avoid becoming a victim of crime on the street and in evening time(TO). Presentation 2.

1. Don't dress provocatively.
2. Don't carry it with you a large sum money.
3. In the evening: Try to avoid sparsely populated and poorly lit places. If you are returning home late, arrange to be picked up or take a taxi. Never use the player, otherwise you will not be able to hear the criminal.
4. When contacting strangers: do not be frank, do not give out your information unless absolutely necessary.
5. Don’t vote on the highway.
6. Use an ATM or pay phone.

Rules of conduct in public places (K). Presentation 3.

1. Don't shop secondhand.
2. Don't take part in gambling.
3. If you have a lot of shopping to do, take a taxi.
4. Change currency only in designated places.
5. If you go shopping or on a holiday with friends, be sure to agree on where you will meet.

Neighborhood in transport (K). Presentation 4. Presentation 5.

1. When purchasing a ticket, remember that in the event of an accident, the cars located in the center of the train are the safest.
2. Do not count money in front of everyone and do not show the contents of your wallet to anyone.
3. Do not gamble with fellow travelers.
4. Do not drink water, lemonade, or beer offered by strangers: they may contain sleeping pills or narcotic substances.
5. Always keep documents and money with you.

Behavior in the entrance of the house, the elevator, on the landing (K). Presentation 6.

1. Do not enter the entrance if a stranger is following you.
2. Do not open when strangers door to my apartment.
3. If there is a threat of attack, make some noise and attract the attention of your neighbors.

Complete the task.

Teacher: You need to answer the following questions:

What are the areas of increased criminal danger?

What are the basic rules of behavior in secluded places?

What conclusions did each of you draw for yourself regarding behavior in extreme situations?

Testing students.

Which of the following rules will you use when returning home in the evening:

A. Use passing transport.
B. Walk along the illuminated sidewalk and as close to the edge as possible.
B. Go the shortest route, running through courtyards, landfills and poorly lit areas.

It seems to you that someone is following you. Your actions:

A. Run towards him.
B. Stop and find out the reason for the pursuit.
B. Cross the street several times and, having convinced yourself that your suspicions are correct, run to a crowded place.

From the examples given, determine the most dangerous time - the time of increased risk to personal safety:

A. Darkness descending on the city center, where people casually stroll and relax.
B. Early morning on a crowded commuter train.
V. Twilight, finding a man alone in a forest park.

Dangerous places at any time of the day can be:

A. Police station, post office, hospital.
B. Vacant lots, abandoned houses, backyards.
B. Banks, hairdresser, fire station.
G. Shop, repair shop, administrative building.

A girl enters her entrance, hears loud screams, laughter and realizes that there is a drunken group on the floor above. Select the option that you could advise the girl:

A. Wait until they leave.
B. Wait for an adult acquaintance to enter the entrance and ask to be escorted to the apartment.
B. Go home calmly.

Answers.