;AB REPORT EXPERIMENT 1: CHEMICAL REACTIONS PDF

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International University, Vietnam National University - HCMC CHEMISTRY LABORATORY

REPORT EXPERIMENT 1: CHEMICAL REACTIONS

Group: _______2_______

Section: _____1_________ Date: ____________

Group members: Seq.

Full name

Student ID

% Signature Contribution (total = 100%)

1

Nguyễn Võ Minh Triết

2

Nguyễn Vũ Nhật Quang ITITIU20149

Quang

3

Trần Tú Nhi

BEBEIU20225

Nhi

4

Huỳnh Thị Thúy Vân

BEBEIU20261

Vân

5

Dương Hoàng Ân

ITITIU20151

Ân

6

Phan Mỹ Hồng Hạnh

BEBEIU20198

HẠNH

BTBCIU20034

Total score: _______/100

0

0

Triết

Score

1

International University, Vietnam National University - HCMC CHEMISTRY LABORATORY

I.

Introduction

A chemical reaction occurs when one or more compounds, known as reactants, are changed into one or more distinct substances, known as products. Chemical elements or compounds are examples of substances. The constituent atoms of the reactants are rearranged in a chemical reaction, resulting in the formation of various substances as products. In this lab session, we will learn by doing and observing the different signs of chemical reactions as well as learn how to classify them. Different chemical reactions will produce different phenomena, by observations we know a change or a chemical reaction has occurred. From this, we synthesize a number of signs such as color change, solid formation, gas release, and heat and light generation. In addition, many chemical reactions may be divided into five categories. Knowing how to forecast the products of unknown reactions requires a detailed grasp of these sorts of reactions. Combination, decomposition, single-replacement, double-replacement, and combustion are the five main kinds of chemical processes. 1. Objective: - Carrying out various chemical reactions, such as precipitation reactions, evaporation processes, acid and base reactions, redox reactions, and complex formation. - Noticing, characterizing, and documenting chemical changes. - Formulating and balancing the chemical equations for the observed processes. 2. Materials and equipment: a. Materials: 0.5M CuSO4

0.1M KI

Distilled water

2M NaOH

3% H2O2

0.5M FeCl3

2M NH4OH

2M H2SO4

2M KOH

0.5M KCl

MnO2

0.5M FeSO4

0.1M AgNO3

0.5M Na2SO3

0.5M Al₂(SO₄)₃

0.5M KBr

6M NaOH

2M HCl

0.1M KMnO4

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b. Equipment: Ten test cubes One test-tube rack One test-tube holder Three beakers Two pasteur droppers One alcohol lamp 2 test tube brush 1 water bath

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International University, Vietnam National University - HCMC CHEMISTRY LABORATORY II.

Experimental

1. Reaction of Cu-2+--: Step 1: Prepare 2 test tubes, 0.5M CuSO4, 2M NaOH, 2M NH4OH. Step 2: Drop 10 drops 0.5M CuSO4 into each test tube. Step 3: Add 10 drops 2M NaOH into tube no.1 and 10 drops 2M NH4OH into tube no.2 Step 4: Mix them well and observe. Step 5: After that, we continue to put 10 drops 2M NaOH into tubes no.1 and 10 drops 2M NH4OH into tubes no.2. Step 6: Blunge tubes lightly and inspect. Step 7: Note the result and clean up according to instructions.

2. Reactions of silver halides: a. Section 1: Reactions of Potassium Chloride (KCl): Step 1: Prepare 2 test tubes, 0.5M KCl, 0.1M AgNO3, 2M NH4OH. Step 2: Drop 10 drops 0.5M KCl into each test tube. Step 3: Then add 0.1M AgNO3 into both test tubes. Step 4: After that, we continue to put 10 drops of 2M NH4OH into tubes no.2. Step 5: Mix tubes lightly and wait at least 2 minutes. Step 6: Observe and record the result and clean up according to instructions. b. Section 2: Reactions of Potassium Bromide (KBr):

Step 1: Prepare 2 test tubes, 0.5M KBr, 0.1M AgNO3, 2M NH4OH. Step 2: Drop 10 drops 0.5M KBr into each test tube. Step 3: Then add 0.1M AgNO3 into both test tubes. Step 4: After that, we continue to put 10 drops of 2M NH4OH into tubes no.2. Step 5: Mix tubes lightly and wait at least 2 minutes. Step 6: View and mention the result and clean up according to instructions.

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International University, Vietnam National University - HCMC CHEMISTRY LABORATORY

3. Reaction of H2O2 : Step 1: Prepare 3 test tubes, 0.1M KMnO4, 2M H2SO4, 0.1M KI, 3% H2O2, MnO2. Step 2: Add 1 drop 0.1M KMnO4 into tube no.1, 5 drops 0.1M KI into tube no.2 and 10 drop 3% H2O2 into tube no.3. Step 3: Then drop 5 drops 2M H2SO4 to 2 tubes no.1 and no.2. In tube no3, we put a dash of MnO2. Step 4: After that, we continue to add 3% H2O2. Step 5: Wait at least 2 minutes after lightly mixing the tubes. Step 6: Observe and record the changes, then clean up as directed.

4. Reactions of KMnO4: Step 1: Prepare 3 test tubes, 0.5M Na2SO3, 2M H2SO4, 6M NaOH, distilled water, 0.1M KMnO4. Step 2: To begin, fill each tube with 10 drops of 0.5M Na2SO3. Step 3: Then drop turn 5 drops 2M H2SO4, 6M NaOH no.2, and 5 drops distilled water into tube no.1, no.2 and no.3. Step 4: Put in to all test tubes 0.1M of KMnO4. Step 5: Mix tubes well and wait at least 2 minutes. Step 6: Observe the changes and make a note of them, then tidy up as advised.

5. Reactions of Fe2+ and Fe3+: a. Section 1: Ferric ion (Fe3+): Step 1: Prepare 2 test tubes, 0.5M FeCl3, 2M KOH, and 2M NH4OH. Step 2: Add 10 drops 0.5M FeCl3 per tube. Step 3: Put 5 drops KOH into tube no.1 and 5 drops 2M NH4OH into tube no.2. Step 4: Put in to all test tubes 0.1M of KMnO4. Step 5: Gently mix them. Step 6: Observe the changes and make a note of them, then clean as conduct.

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International University, Vietnam National University - HCMC CHEMISTRY LABORATORY

b. Section 2: Ferrous ion (Fe2+): Step 1: Prepare 2 test tubes, 0.5M FeSO4, 2M KOH, and 2M NH4OH. Step 2: Add 10 drops 0.5M FeSO4 into both 2 tubes. Step 3: Put 5 drops KOH into tube no.1 and 5 drops 2M NH4OH into tube no.2. Step 4: Put in to all test tubes 0.1M of KMnO4. Step 5: Gently mix them. Step 6: Observe and note the results, then clean according to instructions.

6. Reactions of Al3+: Step 1: Prepare 2 test tubes, 0.5M Al2(SO4)3, 2M NaOH, and 2M HCl. Step 2: Both tubes are dropped 10 drops 0,5M Al2(SO4)3. Step 3: Continue to add 5 drops of 2M NaOH into two tubes. Step 4: Mix the pair test tubes gently and observe the reactions. Step 5: Put 20 drops of 2M HCl into tubes no.1 and 20 drops 2M NaOH into the other tube. Step 6: Observe the changes after mildly mixing tubes and make a note of them, then up following the instructions.

7. Flame test: Step 1: First, we light the Busen burner. Step 2: Then using distilled water, clean the loop. Step 3: Hold the loop in the flame after dousing it in the tested solution. Step 4: After that, we recognize the main color changes of the flame and note them. Step 5: We can calculate the frequency and energy of photons released during flame testing using the wavelengths table.

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III. Results and discussion 1. Reactions of Cu2+ Reaction 0.5M CuSO4 + 2M NaOH

Observation The formation of pale blue precipitate.

Chemical Equation CuSO4 + 2NaOH → Cu(OH)2↓ + Na2SO4

Picture 1: The reaction between 0.5M CuSO4 and 2M NaOH. 0.5M CuSO4 + 2M NH4OH

The blue precipitation dissolves once it is created, and the solution becomes dark blue appears in this reaction.

CuSO4 + 2NH3 + 2H2O → Cu(OH)2↓ + (NH4)2SO4 Cu(OH)2↓ + 4NH3 → [Cu(NH3)4](OH)2  CuSO4 + 6NH3 + 2H2O → (NH4)2SO4 + [Cu(NH3)4](OH)2

Picture 2: The reaction between 0.5M CuSO4 and 2M NH4OH.

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Comments: -

Cu2+ has the property of reacting with OH- to generate blue precipitation. The Cu(OH)2 solution interacts with NH4OH to generate a complex molecule, making reaction number two dark blue.

2. Reactions of silver halides Reaction

Observation Put in AgNO3, the substance turns white, creating precipitate.

Chemical Equation KCl + AgNO3 → KNO3 + AgCl↓

0.5M KCl + 0.1M AgNO3

Picture 1: The reaction between 0.5M KCl and 0.1M AgNO3. This tube has one state, after putting in the AgNO3 the substance turns white. After putting in NH4OH, we observe no color change.

0.5M KCl + 0.1M AgNO3 + 2M NH4OH

Picture 2: The reaction three solutions (0.5M KCl, 0.1M AgNO3, 2M NH4OH)

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AgNO3 + KCl → AgCl↓ + KNO3 AgCl↓ + 2NH4OH → 2H2O + Ag(NH3)2Cl

International University, Vietnam National University - HCMC CHEMISTRY LABORATORY

0.5M KBr + 0.1M AgNO3

0.5M KBr + 0.1M AgNO3 + 2M NH4OH

This tube has one state, after put in AgNO3, the substance turns white, creating precipitation.

Picture 3: The reaction between 0.5M KBr and 0.1M AgNO3. This tube has one state, after putting in AgNO3, the substance turns white, creating precipitate.

AgNO3 + KBr → AgBr↓ + KNO3

AgNO3 + KBr → AgBr↓ + KNO3 AgBr+2NH4OH→2H2O+Ag(NH3)2Br

Picture 4: The reaction three solutions (0.5M KBr, 0.1M AgNO3, 2M NH4OH) Comments: -

In most of our test case, the reaction create precipitate, due to the fact that we have halogens group reacts with silver (AG), create precipitate and make an “exchange reaction”.

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3. Reactions of H2O2 Reaction 0.1M KMnO4 + 2M H2SO4 + H2O2

0.1M KI + 2M H2SO4 + H2O2

Observation The unchanged solution color from KMnO4 to H2SO4, but when adding H2O2 solution will change color from purple to colorless.

Picture 1: The reaction three solutions (0.1M KMnO4, 2M H2SO4 and H2O2) The first step, like test tube 1, has no effect on the color solution. When H2O2 solution is added, the color changes from purple to yellow-brown, with a purple precipitate.

Picture 2: The reaction three solutions (0.1M KI, 2M H2SO4 and H2O2)

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Chemical Equation 2KMnO4 + 3H2SO4+ 5H2O2 → K2SO4 + 2MnSO4 + 8H2O + 5O2↑

2KI + H2SO4 + H2O2 → K2SO4 + 2H2O + I2↓

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H2O2 + MnO2

MnO2 + 2H2O2 → MnO2↓ + O2↑+ 2H2O The dark solid solution does not dissolve.

Picture 3: The reaction between H2O2 and MnO2 Comments: -

H2O2 is an oxidizing agent that participates in redox reactions to exchange electrons, resulting in a change in oxidation number.

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4. Reactions of KMnO4 Reaction 0.5M Na2SO3 + 2M H2SO4 + 0.1M KMnO4

0.5M Na2SO3 + 6M NaOH + 0.1M KMnO4

Observation Chemical Equation The solution changed color from 5Na2SO3 + 3H2SO4 + 2KMnO4 → K2SO4 white to brown, no precipitate was + 2MnSO4 + 5Na2SO4 + 3H2O formed

Picture 1: The reaction between 0.5M Na2SO3 and 0.2M H2SO4 and 0.1M KMnO4 There was no precipitate, and the Na2SO3 + 2NaOH + KMnO4 → K2MnO4 + solution also turned reddish-brown Na2SO4 + Na2MnO4 + H2O

Picture 2: The reaction between 0.5M Na2SO3 and 6M NaOH and 0.1M KMnO4

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0.5M Na2SO3 + H2O + 0.1M KMnO4

The conversion to a dark-brownish 3Na2SO3 + H2O + KMnO4 → 3Na2SO4 + solution 2MnO2 + 2KOH

Picture 3: The reaction between 0.5M Na2SO3 and H20 and 0.1M KMnO4

Comments: -

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The chemical reaction between Na2SO3 and H2SO4 and KMnO4 with the solution turns brown. The reaction of Na2SO3 after reacting with NaOH and KMnO4 respectively will give a reddishbrown solution. The reaction creates a dark-brownish solution mixture after reacting.

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5. A. Reactions of Fe3+ Reaction 0.5M FeCl3 + 2M KOH

0.5M FeCl3 + 2M NH4OH

Observation At the end of the reaction, a reddish-brown precipitate appeared in the solution.

Picture 1: The reaction between 0.5M FeCl3 and 2M KOH Solution creates reddish brown precipitation.

Chemical Equation FeCl3 + 3KOH → Fe(OH)3 + 3KCl

FeCl3 + 3NH4OH → Fe(OH)3 + 3NH4Cl

Picture 2: The reaction between 0.5M FeCl3 and 2M NH4OH Comments: -

When we add FeCl3 solution to both weak and strong alkaline solutions, we get red-brown results. Fe(OH)3 precipitates as a result of the reaction of two ions, Fe3+ and OH-, and we can conclude that this is an ion exchange reaction.

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5. B. Reactions of Fe2+ Reaction 0.5M FeSO4 + 2M KOH

0.5M FeSO4 + 2M NH4OH

Observation At the end of the reaction, a blue-white precipitate appeared in the solution.

Picture 3: The reaction between 0.5M FeSO4 and 2M KOH At the end of the reaction, a blue-white precipitate appeared in the solution.

Chemical Equation FeSO4 + 2KOH → K2SO4 + Fe(OH)2

FeSO4 + 2NH4OH → Fe(OH)2 + (NH4)2SO4

Picture 2: The reaction between 0.5M FeSO4 and 2M NH4OH Comments: -

When we add FeSO4 solution to both weak and strong alkaline solutions, we get blue-white results. Fe(OH)2 precipitates as a result of the reaction of two ions, Fe2+ and OH-, and we can conclude that this is an ion exchange reaction.

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6. Reactions of Al3+ Reaction 0.5M Al2(SO4)3 + 2M NaOH + 2M HCl

0.5M Al2(SO4)3 + 2M NaOH + 2M NaOH

Observation The formation of white colloidal precipitate first. After adding HCl to the solution, the precipitate gradually dissolves by the reaction between Al(OH)3 and HCl.

Picture 1: The phenomena of the reaction between Al2(SO4)3 and NaOH and adding HCl to the solution. The formation of white colloidal precipitate first. After adding NaOH to the solution, the precipitate gradually dissolves by the reaction between Al(OH)3 and NaOH

Picture 2: The phenomena of the reaction between Al2(SO4)3 and NaOH and adding NaOH to the solution.

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Chemical Equation Al2(SO4)3 + 6NaOH --> 2Al(OH)3 + 3Na2SO4 Al(OH)3 + 3HCl --> AlCl3 + 3H2O

Al2(SO4)3 + 6NaOH --> 2Al(OH)3 + 3Na2SO4 Al(OH)3 + NaOH --> NaAlO2 + 2H2O

International University, Vietnam National University - HCMC CHEMISTRY LABORATORY

Comments: The above two reactions indicate that Al3+ is an amphoteric ion because it can react with H+ and OH- in a solution. The formation of a white colloidal precipitate is due to the reaction of Al3+ and OH-. Moreover, the dissolution of the precipitate is due to the reaction between Al(OH)3 and OH- as well as H+.

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7. Flame test Solution

Dominant flame color

Wavelength (nm)

Frequency (s-1)

Photon energy (J)

LiCl

Pink red

701

427960.06

2.836 x 10^-28

NaCl

Orange and Yellow

597

502512.6

3.33 x 10^-28

KCl

Violet

423

709219.9

4.699 x 10^-28

CaCl2

Green and Yellow

577

519930.7

3.45 x 10^-28

BaCl2

Orange

609

492610.8

3.264 x 10^-28

Comments: -

The change of color when holding these solutions in the flame is due to the electron excitation to a higher energy level. Electrons of the atom and metal ions absorb the energy of alcohol lamp to jump to unstable higher energy level.

IV.

Conclusions In conclusion, we were able to categorize synthesis, decomposition, single displacement, double displacement, combustion, acid-base, complex compound formation, and oxidation-reduction processes after the experiment 1. In addition, we may see chemical reaction events such as evaporation (gas release), precipitation, solution color change, and changes in the characteristics of particular solutions after they have been burnt. Although the division work for members went quite smoothly, errors still occur because of small details (such as number or name of equipment used, and missing some images) as well as not marking the experimental numbers after taking pictures, it also causes some difficulties while images into experiments in the report. Therefore, we will learn from the experience next time in taking notes and monitoring the lesson without missing any details.

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