ENGLISH NARRATION

(In a class there is a teacher who is explaining the material to his students about the element 

of halogen that is clor. Where the teacher explains the lesson then returns to the student about his understanding of the material that has been conveyed)

Teacher: good morning children

Student: morning teacher

Teacher: before studying let us pray first, try who will lead the prayer ahead?

Diamon: me, ma'am

Teacher: yes diamond please come forward to lead the prayer

(Prayer underway)

Teacher: At this meeting the mother will explain the material about the clor element.

And the goals of today's learning are:

1. Students can find out what is clor, and how the nature of clor.

2. Students can understand the usefulness of clor

3. Students can know how to make clor elements.

Teacher: ok ... before last week we've already learned about this material. That is about the element of flour. Do children still remember what is flourine.

Fani    : Me, Mom. Flourine is an element in the periodic table that has the symbol F and atomic number 9.

Teacher: yes it is true, Fluorine is an element in the periodic table that has the symbol F and      atomic number 9. Its name is derived from the Latin fluere, meaning "to flow". It is the most chemically and electronegatively reactive yellow-green toxic halogen gas of all the elements. . Well here anyone still remember what use of flourine?

Sinta  : I'm bu ..

Teacher: oh nails ... please forward son

Sinta: Atoms and fluorine molecules are used for plasma etching in semiconductor manufacturing, flat panel display production, and MEMS fabrication. Fluorine is indirectly used in the production of scratch resistant plastics such as teflon, freon production, and in the production process of uranium. Fluorochlorohydrocarbon.

In air conditioners and cooling machines. Fluorine is often added to toothpaste to prevent 

cavities.

Teacher: the greatest waduh the reading turned out to be very smooth yes, children's applause,

 Well after knowing the element of the flourine, the mother will explain the next material about

 clor. Chloros, "pale green"), is a chemical element with the symbol Cl and atomic number 17. 

In the periodic table, this element belongs to the halogen group or group 17 (the old system: 

VII or VIIA). In the form of chloride ions, these are the salt-formers and other compounds

 available in nature in abundant quantities and are necessary for the formation of almost all 

life forms, including humans. In the form of gas, chlorine is greenish yellow, and very 

poisonous. In liquid or solid form, chlorine is often used as an oxidant, bleach, or disinfectant.

 Is there still no understanding?

Rina: already bu ...

Teacher: hemmm ... very clever mother's children. Well, if you already understand it means mother 

who will ask, Who can give us an example of usability from clor.

Sari : I'm mam

Teacher: ok please ...

Sari : Purpose of chlorine element is:

• Chlorine is widely used for water purification because it can kill bacteria.

• Used for the production of DDT, Gamaxane and many more useful compounds.

• Chlorine is used as a bleach.

• It is used for the synthesis of organo compounds such as 1, 2 - dioloroethane and Vinyl chloride.

Teacher: yes ,, right answer. Then can anybody give an example of the act of clor element?

Reni : I'm mam

Teacher: ok please, how about the process of making it?

Sinta : (give examples)

Teacher: Well then the mother will form 6 groups consisting of 4 people

Here the mother will share the elements that you will discuss. The task is that each group

 makes a paper about halogen element, halogen element consists of 7, so group 1 material

 He, group 2 Ne, group 3 Ar, group 4 Kr, group 5 Xe, group 6 Rn. What you will discuss 

is the nature, usefulness and mode of manufacture of these elements. Okay kids because

 the time is up, please this task you do at home and next week gathered. And do not forget 

to understand your material because next week my mother will ask about your each material. 

Well, let's end this meeting today. Please go home and see you next week

Student: (together) walaikumsalam wbr, see you mom.

VOCABULARY OF CHEMISTRY

VOCABULARY OF CHEMISTRY

1.      Substance

A type of matter with a fixed composition.

2.      Element

If all the atoms in a substance has the same identity it becomes {blank}.

3.      Compound

A substance in which the atoms of 2 or more elements are combined.

4.      Heterogeneous Mixture

Mixture in which different materials can easily be distinguished.

5.      Homogeneous Mixture

Contains 2 or more gases, liquids, or solids substances blended evenly.

6.      Solution

Homogeneous mixture with particles so small that they cannot be seen with a microscope.

7.      Colloid

Type of mixture with particles that are larger than those in solutions, but not heavy enough to settle out.

8.      Tyndall Effect

Scattering of light by colloidal particles.

9.      Suspension

Heterogeneous mixture containing a liquid where visible particles settle.

10.  Physical Property

Characteristic of a material you can observe without changing the identity.

11.  Distillation

A process for separating substances by evaporating a liquid and recondensing its vapor.

12.  Chemical Property

Characteristic of a substance that indicates whether it can undergo a chemical change.

13.  Chemical Change

A change of one substance to another.

14.  Law of Conservation and Mass

The mass of all substances that are present before a chemical change equals the mass of all the substances after the change.

15.  Kinetic Theory

Explanation of how particles in matter behave.

16.  Melting Point

The point in temperature when the solid starts to liquefy.

17.  Heat of Fusion

The energy required to change a substance from a solid to a liquid at its melting point.

18.  Acid

 An acid is a compound with a pH of less than 7 that forms hydrogen ions when dissolved in water. Acids react when coming into contact with bases and some metals to form salts.

19.  Alkali metals

The alkali metals are the elements in the first column of the periodic table with the exception of hydrogen.

20.  Protons

Particles in a atom with a positive charge.

21.  Neutrons

Particles in a atom with no charge.

22.  Electrons

Particles in a atom with a negative charge.

23.  Quarks

Smaller particles in neutrons and protons.

24.  Electron Cloud

Area around a nucleus where electrons are mostly found.

25.  Atomic Number

Number of protons in an atom is equal to a number called {blank}.

26.  Mass Number

This number is the sum of the number of protons and neutrons.

27.  Isotopes

Atoms of the same element that have different numbers of neutrons.

28.  .Metals

Good conductors of heat and electricity.

29.  Metallic Bonding

Positively charged metallic ions surrounded by a electron cloud.

30.  Transitional Elements

Between groups 1 and 2, and 13 and 18.

31.  Nonmetals

Usually gasses or brittle solids at room temperature.

32.  Diatomic Molecule

Consists of 2 atoms of the same element in a covalent compound.

33.  Sublimation

The process of a solid going directly into a vapor.

34.  Metalloids

Has properties of both nonmetals and metals.

35.  Empirical formula

 The composition of a compound in terms of the relative numbers and kinds of atoms in the simplest ratio. 

36.  Semiconductors

Elements that conduct under circumstances.

37.  Chemical Formula

A formula that shows what elements are in a compound and what it will become.

38.  Chemical Bond

Force that holds atoms together in a compound.

39.  Ionic Bond

Force of attraction between opposite charges.

40.  Oxidation Number

Tells you how many electrons an atom has gained or lost.

CAUSE AND EFFECT CHEMICAL REACTION

ACID RAIN

Definition of acid rain

The notion of acid rain is a process when the descending rain brings with it pollutant particles such as sulfur dioxide gas. If it rains, the rain takes the particles in the air down, then into the soil or the water. If there is no air pollution, rainwater does not negatively affect the life of the soil and water.

Causes of acid rain

 The process of acid rain usually occurs when air pollution levels are above or above the normal threshold. Industrial power plants, oil refineries that use coal as fuel are the main source of acid rain. Sulfur and nitrogen in burned coal will turn into sulfur dioxide (SO2) and nitrogen oxide (NO) gases. These gases mix with the surrounding air and move with the wind to another place. The rain water brings SO2 and NO gases into the soil or drains. In the air the gases of NO and SO2 can be oxidized and react with water to form nitric and sulfuric acid or ammonium sulfate. Rainwater carrying sulfuric acid or ammonium sulfate and nitric acid down and seep into the soil or stream, and cause the degree of acidity of water or soil to be high (pH becomes low).

The effect of acid rain Acid rain

can release soil nutrients such as calcium and magnesium from the soil and bring it to rivers and ponds. Acid rain causes the river water to become too acidic so some aquatic animals such as fish, amphibian eggs threatened his life. Acid rain also causes toxic metal deposits such as mercury (HgO) and aluminum (Al2O3) oxides dissolved in water so that animals can be poisoned. Acid rain also can accelerate the occurrence of metal-metal casts such as iron, steel, and copper. However, acid rain is not very influential in calcareous mountain areas (bases), because lime can neutralize acid in rainwater.

How to prevent acid rain

Long-term effort to stop the damage caused by acid rain is to stop the source, replacing the coal fuel with other fuels. Meanwhile, the handling of a quick way if acid rain is happening is to spread the limestone above the lake or river.

2. CORROSION

 

      Corrosion is a redox reaction between a metal and various substances in the environment that produce undesirable compounds. In ordinary language, corrosion is called kararatan. The most common example of corrosion is iron corrosion. In corrosion events, the metal undergoes oxidation, while oxygen (air) is reduced. The metal rust is generally a form of oxide and carbonate. The chemical rust formula is Fe2O3. XH2O, a solid brown-red solid. Corrosion is an electrochemical process. In iron corrosion, certain parts of the iron act as anode, in which iron undergoes oxidation.

Fe (s) ↔ Fe2 + (aq) + 2e Eº = +0.44 V

The freed electrons in the anode flow into the other part of the iron acting as a cathode, in which the oxygen is reduced.

O2 (g) + 2H2O (l) + 4e ↔ 4OH- (aq) Eº = +0.40 V

Or O2 (g) + 4H + (aq) + 4e ↔ 2H2O (l) Eº = +1.23 V

The iron ions (II) formed at the anode subsequently oxidized to form iron (III) ions which then form the hydrated oxide compound, Fe2O3. XH2O, which is iron rust. As to which part of the iron acts as anode and which part acts as a cathode, it depends on various factors, such as impurities, or the density of the metal.

Causes of corrosion

Corrosion occurs because of the reaction between the metal and the substances around it.  
In rust, rust can occur because moist air (oxygen and water) corrodes (reacts) to the iron so

 that a new substance appears, reddish brown solids.

Effect of Corrosion

  Metals suffering from corrosion will become porous, so their strength decreases. 
Buildings, machinery, bridges, consume iron as the main support of the frame. So that the 

iron porosity can cause the collapse of the building and the malfunction of the machines.

How to prevent corrosion

 1. Paint

 2. Oil with Oil or Grease

 3. Wrapped With Plastic

4. Tin Plating (coating with tin)

5. Galvanization (coating with zinc)

6. Cromium plating (coating with chromium)

7. Sacrifical Protection (sacrifice anode)