A Simple Identification of Chemical Reactions

1.        Titles

The Identification of Chemical Reactions

2.      Objectives

To Identify the chemical reactions

3.      Theory

Such basic (intrinsic) characteristics consist of a substance’s color, odor, solubility and state of matter (that is, is it a solid, liquid, or gas at room conditions). Thus, these indicators reflect a change in one or more of these attributes. In this activity, we will explore several indicators using solutions of two substances that will be added together. If two solutions are poured together and an indicator is observed, then we conclude that a new substance has been produced and that a chemical reaction has taken place. Those indicators are:

1. Change in color. Here the color change must not be merely a dilution of a

beginning color (like diluting blue food coloring with water). A different color or a definite hue change must occur.

2. Change in odor. Although this characteristic seems obvious, it is often hard to detect. The proper way to smell a substance is to hold the test tube or container 4-6 inches from the nose and waft (fan) the air above the container towards the face.

3. Formation of a gas. If a substance is a solid under room conditions and is

changed to a new substance that is a gas at room temperature, then this new

substance can be detected by bubbling or fizzing of a solution. (Note that this is without the addition of heat.)

4.      Formation of a precipitate. If a substance is soluble in water and is changed to a new substance that is insoluble, a solid will appear in the solution. Some precipitates are quite dense and settle quickly to the bottom of the container. The  Rules of solubility ionic compounds  of ionic compounds is showed below in the back of this report. Others are small, finely divided particles that settle slowly and make the solution appear cloudy. Any interference with light passing through a liquid is indicative of particles floating in the liquid and dispersing the light yso that the liquid is no longer transparent.

5.        Materials

1.      100 ml of water 2.      0,585 gram of Solid of NaCl 3.      HCl 0,1 M 4.      NaOH 0,1 M 5.      AgNO3 0,1 M

6.      Pb(NO3)2 0,1 M 7.      KI 0,1 M 8.      Na2SO4 0,1 M 9.      BaCl2 0,1 M

6.      Equipments

Volumetric flask (1) Termometer (1) Test tube (5) Electrical Balance (1) Watch glass (1)

Spatula (1) Stirring Rod (1) Test tube rack (1) Beaker Glass (2)

7.        Procedures

1. First, I and my my friends prepared a solution as the materials of the lab work. I prepared 100 ml of NaCl 0,1 M by dissolve 0,585 gram of solid NaOH.
2. After the solutions has already done,  The chemical identification is started.
3. First Reaction, HCl_(aq) + NaOH_(aq), A Test tube is taken and filled with ± five drops of HCl. And then , the NaOH is filled  ±  five drops into same test tube. And then the test tube is observed.
4. Second Reaction, A Beaker glass 100 ml is fulfilled  by  water. And the A little cut of solid Sodium is placed on the water slowly. And then, the reaction is
5. The third reaction, AgNO_3(aq) + NaCl_(aq) A Test tube is taken and filled with ± five drops of AgNO₃. And then , the NaCl is filled  ±  five drops into same test tube. And then the test tube is observed.
6. The fourth reaction, Pb(NO₃)_2(aq) + KI_(aq), A Test tube is taken and filled with ± five drops of , Pb(NO₃)₂. And then , the KI is filled  ±  five drops into same test tube. And then the test tube is observed
7. The fifth reaction, Na₂SO_4(aq) + BaCl_2(aq), A Test tube is taken and filled with ± five drops of , Na₂SO₄. And then , the BaCl₂is filled  ±  five drops into same test tube. And then the test tube is observed

8.        Results

No	Reactions	Before mixed	After Mixed
1	HCl(aq) + NaOH(aq)	Both of the solution is colorless	·         Temperature changed, from 30o C into 31o C
2	Na(s) + H2O(l)	The solid sodium has a grey color	·         Temperature changed, from ·         Bubbles is produced ·         The odor changed
3	AgNO3(aq) + NaCl(aq)	Both of the solution is colorless	·         White Precipitate is formed ·         The color  changed, from colorless to white
4	Pb(NO3)2(aq) + KI(aq)	Both of the solution is colorless	·         Yellow precipitate is formed ·         The color changed, from colorless to yellow
5	Na2SO4(aq) + BaCl2(aq)	Both of the solution is colorless	White precipitate is formed The color  changed, from colorless to white

9.      Discussions

1.      HCl_(aq) + NaOH_(aq) à NaCl_(aq) + H₂O_(l). This reaction is happened in the first reaction. The temperature change is occurred because this reaction is belong to exothermic reaction and follow a chemical equation :

HCl_(aq) + NaOH_(aq) à NaCl_(aq) + H₂O_(l)  Δ H = -x. The chemical reaction is known by the change of the temperature

2.      Reaction between Solid sodium with water produce sodium hydroxide and hydrogen gas, follow a chemical equation :

2Na_(s) + 2H₂O_(l) à 2NaOH_(aq) + H_2(g)  ΔH = -x. the reaction is exothermic reaction, because of that, the temperature change. The hydrogen gas is released in bubble form.

3.      Reaction between Silver nitrate with salt produce a precipitate forms of silver chloride and a solution of sodium nitrate,  follow a chemical equation :

AgNO_3(aq) + NaCl_(aq)àAgCl_(s) + NaNO_3(aq)

The precipitate forms because the solid (AgCl) is insoluble in water, that follow a chemical equation :

Ag⁺_(aq) + Cl^-_(aq) à AgCl_(s)

 That is true for all precipitates - the solids are insoluble in aqueous solutions. The color change follow the color of the new compounds. So, the chemical reaction happen if there is a change in color and a formation of precipitate

4.      Reaction between Lead nitrate with Potassium Iodide produce a precipitate forms of Lead iodide and a solution of potassium nitrate,  follow a chemical equation :

Pb(NO₃)_2(aq) + KI_(aq)à PbI_2(s) + KNO_3(aq)

The precipitate forms because the solid (PbI₂) is insoluble in water, that follow a chemical equation :

Pb²⁺_(aq) + 2I^-_(aq) à PbI_2(s)

 That is true for all precipitates - the solids are insoluble in aqueous solutions. The color change follow the color of the new compounds. So, the chemical reaction happen if there is a change in color and a formation of precipitate

5.      Reaction between Sodium Sulphate with Barium Chloride produce a precipitate forms of Barium Sulphate and a solution of Natrium chloride,  follow a chemical equation :

Na₂SO_4(aq) + BaCl_2(aq) à BaSO_4(s) + NaCl_(aq)

The precipitate forms because the solid (BaSO₄) is insoluble in water, that follow a chemical equation :

Ba²⁺_(aq) + SO₄^2-_(aq) à BaSO_4(s)

That is true for all precipitates - the solids are insoluble in aqueous solutions. The color change follow the color of the new compounds. So, the chemical reaction happen if there is a change in color and a formation of precipitate

10.  Conclusions

The Indicators of  Chemical Reactions are :

1.      Change in temperature         2.      Change in Odor 3.      Change in color

4.      Formation of gas 5.      Formation of precipitate

11.  References

Moore, John T.2003. Kimia for Dummies. Bandung : Pakar Raya

Subagia, I Wayan.2005.Buku Penuntun Kimia Dasar I. Singaraja : IKIP Negeri Singaraja

Subagia and Suheimi. 2005. Materi Praktikum Kimia Dasar I. Singaraja : IKIP Negeri Singaraja

Laporan Praktikum 1

1.        Titles

The Separating Process of water-oil mixtures

2.      Objectives

To Separate water-oil mixtures by using their  physicals properties.

3.      Theory

Oil and water have many differences. The first, oil is non polar reagent and water is a polar reagent., so they can not be mixed. The ”Like dissolve like” principle say, a substance will only dissolve in a suitable solvent. Which are polar substances will dissolve in polar substances and non polar substances will dissolve in non  polar substances . Oil and water also have different density. To separate the mixtures of them, their specific mass (massa jenis) can be used as a principle.

4.        Materials

1.      25 ml of water

2.      25 ml of oil

5.      Equipments

• Statif  (1)
• Double clamp (1)
• Separating Funnel 25 ml (1)
• Ring  (1)
• Beaker glass 100 ml (2)
• Graduated Cylinder 25 ml (2)
• Drop pipets (2)

6.        Procedures

1. The first step, The statif, double clamp and the ring are combined.
2. The water and the oil are measured by graduated cylinder, 25 ml  oil and  25 ml  water. After that, they are poured into the separating funnel, and they are shaken
3. After that, the separating funnel is placed in the ring.
4. The beaker glass is put under the separating funnel. We were waiting  until the oil and the water are separated, and then the tap of the funnel is opened to let the liquids come out.
5. The water and oil are measured again.

7.        Results

The mixtures of water  and oil is successfully separated. But there are different volume before and after the separating process

Reagents	Before	After
Water	25 ml	23 ml
Oil	25 ml	24,5 ml

8.      Discussions

From the experiment above, the water-oil mixtures is separated by using ther specific mass. The water is heavier  than oil, so the water take place under the water in the mixtures. So the water and oil can be easily separated.

There are different volume are occurred after the separating process. The reason is, theres still remain water and oil in the separating funnel’s wall, because of the adhesive forces between them,  so the volume are decreased.

9.      Conclusions

The water-oil mixtures is separated by using their specific mass

10.    Question-Answer

1.       What are the differences between oil and water?

The differences are, the water is polar and the oils is non polar. The second, the water’s specific mass is heavier than the oils, or the density of them are different.

2.      Why oil and water cannot be mixed?

The water is polar, and the oil is non-polar.  The ”Like dissolve like” principle say, a substance will only dissolve in a suitable solvent. Which are polar substances will dissolve in polar substances and non polar substances will dissolve in non  polar substances

3.      What is the principle use to separate oil and water ?

The principle use the separate oil and water is the specific mass (density) of each substance.