Pertemuan11 SHOW CAUSE AND EFFECT

CAUSE AND EFFECT

Equation of reaction defined as equation expressing equivalence of Iihat vitamins amount in concerned in reaction of chemistry by using chemical formula. In reaction of chemistry there are Iihat vitamins of pereaksi Iihat vitamins and result of reaction. In writing down equation of reaction, chemical formula of pereaksi written down [in] left internode and chemical formula result of reaction written down by in joint right. Between both that internode [is] attributed to dart (?) expressing direction reaction of chemistry.

Example [of]:

 Metal Magnesium react with chlorine gas form chloride magnesium. Writing down equation of reaction him.

 Equation of reaction him [is] Mg + Cl2 ? Mgcl2

If happened reaction of chemistry, can perceive [by] three kinds of change : Sifatb.Perubahan Susunanc.Perubahan Energisemua a.Perubahan change of chemistry of course mains [at] law pelestarianhukum of law and energi of[is continuation of mass energi. formation of Senyawakimia certain by sure formation law and law comparison of basal berada.Azas which constitute all change of theoretical chemical area kimiamerupakan, correlation [among/between] element concept of dansenyawa fourthly the law above obtained in Teoriasam Dalton, first modern theory [regarding/ hit] molecule and atom of sebagaipartikel basal of Iihat vitamins which grow from this theory [among/between] scale lainadalah, atomic weight relative elements dissolved [by] atomic weight menurutbertambahnya, elements appearance regularly certain dengansifat-sifat push meddeleu tabulate periodicly [of] dariunsur-unsur and forecast the existence of some element which [is] belumdiketahui. Its it[him] and from there proportion relative as atom in set of is smallest [of] compound given by compound formula, [is] wherein used [by] that chemical element device.

            Chemical reactions are chemical change events of substances that react (reactants) to reaction products (products). In the chemical reaction always produced new substances with new properties. Chemical reactions are written using elemental symbols.

A. The characteristics of chemical reactions

When chemical reactions occur, there are changes we can observe. Note the following chemical reaction characteristics.

A. Chemical Reactions May Cause Color Changes: For example we can observe that the purple color in potassium permanganate solution (KMnO4) will change if reacted with oxalic acid solution (H2C2 O4)

This chemical change occurs because the potassium permanganate compound turns into a colorless manganese sulphate (MnSO4) compound. Likewise, the green copper carbonate (CuCO3) will turn into a black-colored copper oxide (Cu2O) and carbon dioxide (CO2) after heating.

B. Chemical Reactions Can Form Sludges

 When barium chloride (BaCl2) is reacted with sodium sulfate (Na2SO4) it will produce a barium sulphate white precipitate (BaSO4). This white precipitate formed is difficult to dissolve in water. The chemical reactions can be written as follows.

          BaCl2 + Na2SO4 → BaSO4 + 2NaCl

         (Solution) (solution) (solid) (solution)

Lots of chemicals reacted to precipitate. Another example is the silver nitrate solution (AgNO3) reacted with sodium chloride solution (NaCl) resulting in a silver white chloride (AgCl) and sodium nitrate (NaNO3) solution.

             AgNO3 + NaCl → AgCl + NaNO3

   (Solution) (solution) (solids) (solution)

Actually what is sediment? The precipitate is a substance that separates itself as a solid phase of the solution. The precipitate may be crystalline or colloidal and may

Removed from the solution by filtration or centrifugation. The precipitate is formed when the solution becomes too saturated with the solute. The solubility of a precipitate is the same

 With the molar concentration of the saturated solution. The solubility solubility increases with increasing temperature, although in some special cases (such as potassium sulfate),

Going the other way around. The rate of increase in solubility with different temperatures. In some cases, changes in solubility with changing temperature may be the reason for separation.

 For example the separation of lead ions from silver and mercury (I) can be achieved by depositing the three ions initially as chlorides, continued by adding hot water to the mixture. Hot water will dissolve lead chloride (PbCl2) but silver and mercury (I) chloride (HgCl) does not dissolve in it. After filtering the hot solution, lead ions will be found in the filtrate.

C. Chemical Reactions May Cause Temperature Changes

 You can prove that chemical reactions can cause temperature changes. In the experiments reacting sulfuric acid (H2SO4) and sodium hydroxide (NaOH) there was an increase in temperature. Well, a chemical reaction that produces a temperature rise is called an exothermic reaction. Exothermic reactions can be found in paper burning and gasoline combustion in motor vehicles. In the second experiment, when you react the mixture of barium hydroxide (Ba (OH) 2) and ammonium chloride (NH4Cl) , The solution will absorb the heat around it resulting in a decrease in temperature. The chemical reaction that absorbs heat around it is called the endothermic reaction. Examples of endothermic reactions in everyday life are photosynthesis and food cooking.

D. Chemical Reactions Cause Gas

 Have you ever dissolved high calcium vitamin tablets (effervescent tablets) into a glass of water? When you dissolve high calcium vitamin tablets into a glass of water, you will see bubbles of gas emerging from the solution. This proves that in the event of a chemical reaction can cause gas. In addition to the above example, you can also observe chemical reactions

Which produces gas when you open carbonated drink cans.

B. Types of chemical reactions

1. Burning reaction

Combustion reaction is a type of chemical reaction in which a compound together with oxygen react with each other so that the formation of new compounds consisting of oxygen.

The main characteristic of this reaction is that the role of oxygen is quite large, as has been known the availability of oxygen is an absolute requirement of a propane combustion reaction that produces a new substance of carbon dioxide

Reaction example: C3H8 + O2 à CO2 + H2O

2. Reaction of merging

The merging reaction is a type of chemical reaction that occurs formation of a new substance comprising the substances forming the substance. The coalescing reaction is also called the forming reaction. The main concept of the reaction is that the new substance that is formed must come from the reaction between the substances.

Reaction Example: xample of the above reaction is the reaction of water formation from the formation of its constituents, namely Hydrogen and Oxygen. At the initial state and room temperature, the forming agents can not be encountered in the form of monoatomic elements (elements formed only from one atom). Under normal circumstances, elements such as hydrogen and oxygen consist of two atoms called diatomic elements.

3. Decomposition reaction

The decomposition reaction is a chemical reaction that occurs where larger and more complex substances are decomposed into their sulfur substances. When noticed, this type of chemical reaction is the opposite of a merger or forming reaction. For more details see the following example of the reaction.

HCl

As is the case with the reaction of the formation of substances formed from the decomposition reaction must also form into stable substances from the forming elements.

4. Metathetic reaction

Metathetic reaction is the exchange reaction of two ectolite-forming ions of certain salts. The reaction may occur when one of the reactants or the desired reaction product has a low moisture in the water (solvent). In other words, this reaction can occur when the sludge precipitates as the final product of the reaction.

Reaction Example:

NaCl + AgNO3 -> AgCl + NaNO3

Daftar Pustaka

Keenan, A. Hadyana Pudjaatmaja, PH. CL, 1992,Kimia Untuk Universitas, Jilid 1, Erlangga,

           Bandung.

Petrucci, H. Ralph, Suminar,1989,Kimia Dasar , Edisi Ke-4 Jilid 1, Erlangga,Jakarta