Using English to Report

EXPERIMENT 2UNITS AND IDENTIFICATION OF ELEMENTS

Day / Date: Monday, 13 February 2017

I.          Purpose

1.      Can test the acidity of elements in the periodic table

2.      Can observe the test flame and the reaction of some of the alkali and alkaline earth

3.      Get to know the reaction of chlorine and halide

4.      Can meneganalisis solution is that mengendung of alkali or alkaline earth

II.        Questions of  Prapraktek

1.      Write down the elements, including the IA (alkali) and the IIA (alkaline) !
Answer:
Group IA:
• H (hydrogen)
• Li (Lithium)
• Na (sodium)
• K (Potassium)
• Rb (Rubidium)
• Cs (Cesium)
• Fr (Francium)
Group IIA:
• Be (beryllium)
• Mg (Magnesium)
• Ca (Calcium)
• Sr (Strontium)
• Ba (Barium)
• Ra (radium)

2.      Completed the following equation:
Answer:
a.   CaCl₂  +  (NH₄)₂ CO₃   → CaCO₃  +  2 NH ₄Cl

b.      BaCl₂  +  (NH₄)₂ CO₃   → BaCO₃  +  2 NH₄Cl

c.       2 NaCl  + (NH₄)₂ CO₃ →  Na₂CO₃  +  2 NH₄Cl

d.      NaCl  +  Cl                  →  Not React

e.       2 NaBr  +  Cl₂             →  2NaCl   +  Br₂

f.       2 NaI  +  Cl₂                →  2 NaCl  +  I₂

3.      Does the addition of CCl4 function in trial C?
Answer:

To identify the elements that are in the solution by looking at the presence or absence of precipitation in solution.

III.       Theoretical Framework

Test the flame can be observed from a solution of the very few to use nichrome wire. By dipping a nichrome wire into a solution and then burn it on a hot flame (flame blue) will be observed flame color of the element. The solution used is a solution of salt of the element. Each element will give different color flame, eg sodium give a yellow flame, a solution of copper green flame, flame red solution of lithium.

On a typical elements. Color yellow flame cutting is a practical way to determine the element sodium. This is a flame test can be used to determine the solution that is not known. Halide salts and alkali and alkaline earth metals can react with halogens are more oxidizing, which form of halogen halide. Rank oxidizing power is F₂ > Cl₂ > Br₂ > I₂. F₂ can oxidize Cl into Cl₂ and Cl₂ can oxidize Br^- to Br₂ and so on. While Br₂ can not oxidize Cl into Cl₂. The reaction can be seen as follows:
Cl₂ + Br^-  →   Cl + Br₂
Cl₂ + I^-  →   Cl + I₂
Br₂ + Cl^-  →   Not react

In reaction to obtain chlorine can be made water chlorine by heating a mixture of MnO2 with HCl 6 M. heater used enough light spirits. The gas formed is passed into distilled water. The equation:
MnO₂ + 4HCl  →  MnCl₂ +  2H₂O + Cl₂. (Epinur, dkk.2013: 25-26)

Halogen elements in the periodic table are included in the VIIA. Making these elements can be done with the Laboratory way that is not too difficult. Manufacture of chlorine based on the oxidation of chloride ions:
2Cl^- + Conductor →  Cl₂ + Reduction

Oxidizing agent, which can be used in an acid solution, for example MnO₂, MnO₄^-, Cr₂O₇^2-, PbO₂. Manufacturing also bromine ions by oxidation by Br-oxidizing agent such as those used in the manufacture of chlorine. In addition, bromine can also be made by oxidizing bromide ions with chlorine.
Cl₂ + 2Br^-  →  2Cl^- + Br₂
The Yod, I₂, can be made by oxidizing ions I
Cl₂ + 2I^-  →  2Cl^- + I₂

Yod precipitated were separated by filtration of an iodine, such as sodium iodine, SiO₂. Yod can be obtained by reduction with sodium hydrogen sulfite. From the electrode potential can be seen that the Cl₂ can oxidize bromide ions and iodide ions.

Alkali metals and alkaline earth metals are called light, hence its density small. All this metal reacts strongly with water, releasing hydrogen and produce a strong base. This element has a valence electron than 1 between the elements in period 1, then the radius of alkali metal atoms to the largest. The valence electrons that are easily removable so that the alkali metals including the most electropositive element. In this group, the more downward relative.

Metal-alkaline earth metal, have 2 valence electrons only 1 degree of oxidation +2. This element can also be known by checking the color of the flame of change salts. (Ahmad Hiskia. 1993: 119-126)

The elements in group 1 had a lot in common chemical properties. The chemical properties are determined by the valence electrons, ie electrons on the outer skin of the track, because the valence electrons of the same class of its own chemical properties are the same.
A.        Group IA

Elements of this group is very reactive and electropositive. Because of its reactivity is not available in the free state in nature. Francium is a radioactive element. All the elements of this group is a strong reducing agent and has a density that is lower. In bunsen flame lithium ion red, yellow sodium, potassium purple, rubidium and cesium red blue.

B.        Group VIIA

Elements of this group is very electronegative, which means easy to form ion nesotif x1. These elements form a diatomic molecule F₂, Cl₂, Br₂, and I₂. At a temperature of chlorine gas in the form of a yellow-green, bromine liquid red-brown. Iodine is a solid black flower and gaseous yellowish.
C.        Noble Gases

Group consisting of helium, neon, argon, krypton, ksenon, and radon. Some of the properties of the elements of this group. Atoms of these noble gases all have a full set of electrons is 8 electrons. The outer skin trajectory electron configurations so are very stable, and therefore over the years are not known compounds of the noble gases. New in 1962 found that M Bartlet ksenon can react with Pt. F₆ form XePtF₆ since gained compounds ksenon then many experts investigating the noble gas compound. From ksenon have known many compounds, such as XeF₂, XeF₆, XeOF₄, XeO₂F₂ and XeO₃.
D.        Elements Transition

In every long period between the IIA and IIIA are elements named the transition. These elements are elements with an atomic number = 21-30, 34-48, 57-78, and 89-120. All elements are transition metals, except gold (yellow) and copper (red). These elements like iron or tin. Equation chemistry looks at the period of the Group. Especially in the group VIIIB very similar to each other. In general, these metals:
1. Total eektron the outer shell remains
2. The melting point and a high boiling point
3. The radius of an atom matching
4. Energy potential only slightly increases with increasing atomic number. (Sukardjo.1990: 375-377).

After the chemical elements found in considerable amounts, people try to learn the chemical elements is systematic. Various attempts have been made to establish the classification of the elements on the basis of common specific traits.

Efforts began to classify the elements into metals and non-metals. Elements such as gold, silver, and copper as the metal, are elements such as oxygen, nitrogen, and sulfur, including the non-metal. This classification is then determined to be less satisfying for their elements have properties between metals and non-metals, such as arsenic and antimen.

Classification of the next classification is based on the valence of the elements, the classification is also not satisfactory because the elements that have the same valence, such as sodium and chlorine, but it is very different.
After Dalton's atomic theory, people are trying to link the properties of various elements with their atomic weights. JW Dobereiner in 1817 compiled the elements that are the same with each group consisting of 3 elements of the group called Triad. It found that in the Triad, the atomic weight of elements being equal to the average of the atomic weights before and after.

Classification of the next classification is held by J.A Newlands in 1864-1866. The elements at the time was known ordered by atomic weight greater. It found that the elements of an eighth element, has properties similar to the elements of the review. So after each of the seven elements of a repetition of its chemical properties. Thus we get a series of elements which comprises seven elements. Therefore it resembles the music charts, called Newlands letter octave of these elements (Soetopo.1990: 366-368).

The elements composing the manufacture of chlorine-scale industry and its relationship with the 2 basic compound that is an important sodium carbonate and sodium hydroxide. This element of the compound is highly reactive and toxic, but other compounds are very different nature of the compound chosen to be used it is moist (inert) and non-toxic. In the right conditions, the fluorine forms compounds with nearly all the elements, the only exception is with helium, neon, and argon.

Swedish chemist Karl Scheele soledad in 1774 and made in the form of hydrochloric acid by reaction with pirolusit, a mineral containing MnO2:
4HCl (aq) + MnO₂ (g) → Cl ₂ (g) + MnCl₂ (aq) + 2H₂O (l)

Schele not realize that greenish-yellow gas that is dihasikannya element and it continues to Humpsy Davy identified in 1811 and named it (the Greek word, means chlorus "green"). Meanwhile Berthallet and Clesaussare have described the nature of chlorine bleach in 1786. However, the chlorine less than satisfactory in some respects: these substances will damage the clothes unless carefully monitored.

Chlorine, bromine, and iodine have more in common with each other stu nature of the Fluorine, the properties particularly describe the production of chlorine and its role in the manufacture of bleaching agents (David Oxtoby.2003: 246, 247-249).

IV.       Equipment and Materials

1.       Tool

·         Test tube

·         Test tube rack

·         Nichrome wire

·         Bunsen

·         Pipette drops

·         Brace wood

·         Lighters

·         napkins / tissues

2.      Materials

·         Solution BaCl₂ 0.5M

·         Solution CaCl₂ 0.5M

·         Solution LiCl 0.5M

·         Solution 0.5 M KCl

·         Solution of NaCl 0.5 M

·         Solution RCL 0.5M

·         Solution NaI  0.5M

·         Solution NaBr 0,5 M

·         Solution of concentrated HCl 12 M

·         Solution (NH₄)₂CO₃ 0.5M

·         Solution (NH₄)₂SO₄ 0.5 M

·         Solution (NH₄) ₃ PO₄ 0.5 M

·         Tetrachloride solution

·         Nitric acid aqueous 6 M

·         Distilled water (distilled water)

·         Water Chlorine

·         The solution is (X)

·         The solution is (Y)

V.        Procedures

A.  Test for the flame alkali and alkaline earth

1)      Place the six test tubes in a rack. Add to it each 2 ml 0.5M BaCl₂; CaCl₂ 0.5M; LiCl 0.5M; 0.5M KCl; 0.5M NaCl; RCL 0.5M.

2)      Take a nichrome wire, heat on the blue flame of a Bunsen. Heat continues until no more color arising on fire. To prevent contamination, do not even touch the nichrome wire net.

3)      Dip the wire into the tube containing barium solution, and heat the tip of the wire to the flame. Record your observations. Clean the wire and repeat the test flame to a solution containing calcium, lithium, strontium and natriun.

Note: For memebersihkan wire used, dip the wire into a solution of concentrated HCl (12 M) and heat until brown, if necessary, repeat this procedure.

B.  The reactions of alkali and alkaline earth

1)      Add 1 ml solution of ammonium carbonate, 0.5 M in each tube. If a precipitate is formed, the sheet write EDP report when there is no reaction, write TR.

2)      Clean the test tube and rinse with distilled water. Enter 2 ml of barium, calcium, lithium, potassium, sodium and strontium, respectively in a test tube. Add 1 ml solution of ammonium phosphate to 0.5 M in each tube. Record your observations.

3)      Clean the tube and add 1 ml of barium, calcium, lithium, potassium, sodium, strontium and into a separate fund. Add 1 ml solution of ammonium sulfate into each tube and record your observations.

C.     Reactions halide

1)      Place the three test tubes in a rack. Add 1 ml of the following solutions in each tube: NaCl 0.5 M; NaBr 0.5 M; Nal 0.5 M.

2)      Into each tube add 1 ml of carbon tetrachloride, 1 ml of water chlorine, and 5 drops of dilute nitric acid (6 M)

3)      Shake each tube and observe the color of the layer of carbon tetrachloride in the bottom.

Note: Dispose of this solution into a special container for organic waste.

D.    Analysis of the solution

1)      Have a total solution (X) to an assistant. Test flame and record your observations.

2)      Add 1 ml each into three test tubes. Add 1 ml of ammonium carbonate to the first test tube, 1 ml of ammonium phosphate to the second tube, and 1 ml of ammonium sulfate to a third tube, record your observations.

3)      Add 1 mL of the solution is (Y) into a test tube. Add 1 ml of carbon tetrachloride, 1 ml of water chlorine, and a drop of nitric acid. Shake the test tube and note the color of the layer of carbon tetrachloride.

4)      Compare the test flame reaction solution X with a sixth solution is known (procedures A and B). State of alkalinity that in the solution X.

5)      Compare the test flame halide solution Y with a third solution is known (procedure C). State of alkalinity that in the solution Y.

VI.       Observation Data

A.    test for the flame alkali and alkaline earth

No	Substance	Color Flame	Evidence
1. 2. 3. 4. 5. 6.	CaCl2 BaCl2 SrCl2 KCl NaCl LiCl	Red Yellow Red brick Blue Orange Red hearts	Alkaline soil Alkaline soil Alkaline soil Alkali Alkali Alkali

B.     The reactions of alkali and alkaline earth

No	Substance	Reagents	EDP	TR
1. 2. 3. 4. 5. 6.	CaCl2 BaCl2 SrCl2 KCl NaCl LiCl	(NH4)2CO3	v v v - - -	- - - v v v
No	Substance	Reagents	EDP	TR
1. 2. 3. 4. 5. 6.	CaCl2 BaCl2 SrCl2 KCl NaCl LiCl	(NH4)3PO4	v v v - - -	- - - v v v
No	Substance	Reagents	EDP	TR
1. 2. 3. 4. 5. 6.	CaCl2 BaCl2 SrCl2 KCl NaCl LiCl	(NH4)2SO4	v v v - - -	- - - v v v

C.     Reactions halide

No.	Substance	Color Flame
1.	NaCl + Cl2	Clear
2.	NaBr + Cl2	Orange yellowish
3.	NaI + Cl2	Red

D.    Analysis of the solution

a.       Substance X
• Flash Color substance X = Purple
• X + (NH4) 2CO3 → TR
• X + (NH4¬) H3PO4 → TR
• X + (NH4) 2SO4 → TR

Conclusions: This substance is KCl

b.      Substance Y
Substance Y + CCl4 + HNO3 → There Deposition
Color Layer CCl4 = red brick
Conclusions: This substance is NaI

VII.     Discussion
A.        On Test for Elements Alkali and Alkaline Earth

Elements of the alkali and alkaline earth elements are very reactive. Elements of the alkali and alkaline earth also give a different color to the flame. Test Flash is commonly used to identify the elements of the alkali and alkaline earth. The electrons in an atom can be moved from one skin to another skin. When the electrons move from the skin of the lower emission of energy in the form of electromagnetic radiation with a wavelength specific. If the radiation is in the visible light, then you will notice the color.
Here are the results of testing on the flame color elements of the alkali and alkaline earth has done.
The alkali and flame color
1. KCl : Blue
2. NaCl : Orange
3. LiCl : Red Hearts
The alkaline earth and flame color
1. CaCl₂ : Red
2. BaCl₂ : Yellow
3. SrCl₂ : Red brick

Based on the above experiment, testing the flame color on the elements of the alkali and alkaline earth except in accordance with his theory of the alkali chloride is colored orange as the color of NaCl is actually yellow. This is due to lack of attention in the color that appears in the flame (Bunsen).

B.     The reactions of alkali and alkaline earth

Reaction correcting element of alkali and alkaline earth on CaCl₂  is reacted with (NH₄)₂CO₃  the results of the experiment is to form a precipitate, because CaCl₂ can react with (NH₄)₂CO₃  with the following reaction:

CaCl₂ (aq) + (NH₄)₂CO₃ (l) → CaCO₃ (s) + 2NH₄Cl (aq)

If CaCl₂ is reacted with (NH₄)₃PO₄  experimental results are precipitated because CaCl₂ can react with  (NH₄)₃PO₄  and the mixing is called heterogeneous solution because there is sediment in the solution and the following reaction:

3CaCl₂ (aq) + (NH₄)₃PO₄ (l) → Ca₃(PO₄)₂ (s) + 6H₄Cl (l)

If  CaCl₂ reacted with (NH₄)₂SO₄  experimental results are CaCl₂ is reacted unable to react with (NH₄)₂SO₄   form deposits are not so visible, because the solution is homogeneous, do not differentiate between solvent and dissolved following reaction.
BaCl₂ is reacted with (NH₄)₂CO₃   then the precipitate is formed the solution is heterogeneous solution:

BaCl₂ (l) + (NH₄)₂CO₃ (l) → BaCO₃ (s) + 2NH₄Cl (l)

If the BaCl2 is reacted with (NH₄)₃PO₄   heterogeneous results, form a precipitate, the reaction is:

BaCl₂ (l) + (NH₄)₂PO₄ (l) → BaPO₄ (s) + 6H₄Cl (l)

If the BaCl₂ reacted with  (NH₄)₃PO₄  results are also heterogeneous precipitation on the solvent, the following chemical reactions:

BaCl₂ (l) + (NH₄)₂SO₄ (l) → BaSO₃ (s) + 6H₄Cl (l)

SrCl₂ is reacted with  (NH₄)₃PO₄   result heterogeneous solution is precipitated on the following reaction:

3 SrCl₂  +  (NH₄)₃PO₄   (l) → Sr₃(PO₄)₂ (s) + 6NH₄Cl (l)

If SrCl₂ is reacted with (NH₄)₂CO₃   the results are also heterogeneous sediments in the solution. as well as SrCl₂ and (NH₄)₂SO₄   also include heterogeneous solution is precipitated in solution is. This is because both compounds can react with the reaction of others.

C.     Reactions halide

In experiments halide reactions involving one of an alkali metal such as sodium, which is a metallic element tends to oxidize (remove electrons), so that all metals have properties reductant. There is a metal that is a weak reductant. For example NaCl + C₆H₄ + HNO₃ + Cl. Sodium can react with acidic solutions, for his lies to the left H.
Halide salts and alkali and alkaline earth metals can react with halogens are more oxidizing, which form of halogen halide. Rank oxidizing power is F₂> Cl₂> Br₂> I₂. F₂ can oxidize Cl into Cl₂ and Cl₂ can oxidize Br^- to Br₂ and so on. While Br₂ can not oxidize Cl into Cl₂. Here the colors are available:

No.	Subtance	Color solution Hexane
1.	NaCl + Cl2	The top layer of transparent, slightly yellow undercoat
2.	NaBr + Cl2	The top layer of yellowish-orange, the bottom layer of clear
3.	NaI + Cl2	The top layer of reddish-purple, red undercoat

D.     Analysis of the solution

By observing the flame test of alkali and alkaline earth metals, and substance X test flame and the flame color purple and mixed with a solution of (NH₄)₂CO₃, (NH₄)₃PO₄ and (NH₄)₂SO₄  precipitation is not experienced. And it can be concluded this substance is potassium chloride (KCl). While the substance Y when added CCl₄ and precipitates HNO₃ (EDP) and the color layer CCl₄ is red brick, it can be concluded that the substance Y is a NaI.

VIII.   Post Practice Questions

1.      What is the reaction flame can be used to identify the elements? Explain your answers
Answer:
No, because the test flame is one hallmark of an element. Fereksitasi element for heating is one hallmark of an element that emits the emission spectrum was observed as a beam of light of a certain color. However, to ensure the accuracy and elements can be identified through the flame test just because it may cause confusion substances are almost the same color in one group or different groups. Therefore, in addition to a flame test can be carried out the precipitation reaction, the reaction of halides and other reactions in order to obtain results more uncertain.

2.      Why is the reaction of chlorine with water NaCl, NaBr and NaI give different results?
Answer:
Because each element has a degree of halogen oxidizing different. Power oxidizing halogen elements from top to bottom to the small halogen above can oxidize halides bottom, but not vice versa.

3.      Why did the IA provide different results with the group IIA B.1,2 on experiments, and 3?
Answer:
Because unsure IA more reactive elements of the IIA, that the trial of the IIA has a higher density than the IA so easily settled.

IX.     Conclusion

Based on the experimental results and observations, we can conclude several things:

1)      In the periodic table, each element is in group and a certain period, so that there is a group that has a group and have the same properties

2)      Test the Flash elements and the alakali alkaline soil.
Color Flash elements IA (alkali), namely:

·        Li (red)

·        Na (yellow)

·        K (purple)

·        Rb (red brick)

·        Cs (blue)

Color Flash elements of the IIA (alkaline), namely:

·        Be (white)

·         Mg (white)

·         Ca (red)

·        Ba (red-orange)

·         Ra (green)

3)      The water reacts with chlorine ions Br and I^- to form a precipitate, the precipitate Br yellowish orange on the top layer, the first precipitation berwrna reddish purple on the top layer. The water reacts with chlorine ion Cl until the trial is formed layer translucent color and somewhat turbid.

4)      Substance X identified by the practitioner of the experimental results is KCl and substance Y is NaI.

X.                 Bibliography

Ahmad, Hezekiah. 1993. Field Fundamentals of Chemistry. Jakarta: Ministry of Education

Epinur, et al. 2013. Field Practical Chemistry. Jambi : Jambi University

Oxtoby, David. 2003. Principles of Modern Chemistry. Jakarta : Erlangga

Soetopo. 1990. Principles of Applied Chemistry. Jakarta: Yudhisthira

Sukardjo. 1990. Basic Chemistry. Jakarta : Erlangga