Lab Report 4: Chemical equilibrium - Chemistry Laboratory | Trường Đại học Quốc tế, Đại học Quốc gia Thành phố HCM

International University, Vietnam National University - HCMC 1 CHEMISTRY LABORATORY REPORT
EXPERIMENT 4: CHEMICAL EQUILIBRIUM
Group: _____________ Section: ______4________ Date: ____________ Group members: Seq. Full name Student ID % Signature Score contribution (total = 100%) 1 2 3 4 5 Total score: ________/15__ Present well: + 1 point Clear picture: + 1 point Total = 15 points
The report must be typed and handed in together with the signed data sheet by the deadline
International University, Vietnam National University - HCMC 2 CHEMISTRY LABORATORY I. Introduction (1 pt)
(Introduce what experiments you do in this report) II. Experimental (1 pt) a. Equipment − 10 test tubes − 1 test tube rack − 1 test tube holder − 1 graduated pipette − 1 cylinder − 3 beakers − 1 distilled water bottle b. Experimental
1. ACID/BASE EQUILIBRIA
1. Step 1: Set up 3 test tubes, 0.5M K2CrO4, Concentrated, 6M NaOH. Label each tube with the number.
2. Step 2: Fill each tube with 10 drops of 0.5M K2CrO4. Then observe the color of tube #1.
3. Step 3: In tubes #2 and #3, add 5 drops of concentrated HCl. Observe the
color of them and compare with tube #1.
4. Step 4: Next, put 10 drops of 6M NaOH into tube #3. Observe and compare
the color of tube #3 with tube #2.
2. EQUILIBRIA OF ACID/BASE INDICATORS
1. Step 1: Prepare a test tube with 2 drops of methyl violet.
2. Step 2: Fill this tube with 20mL of distilled water.
3. Step 3: Then divide it equally into 2 test tubes. Observe the color of tube #1.
4. Step 4: Carefully add 6M HCl to tube #2 until there is no noticeable change. Observe how the color changes.
5. Step 5: Next, continue adding 6M NaOH to tube #2 wisely until there is no
significant change. Observe the shift in color.
6. Step 6: After then, add 6M HCl wisely to tube #2 until there is no discernible
change. Observe the shift in color.
3. COMPLEX ION FORMATION (Skip)
4. EQUILIBRIA OF PRECIPITATION REACTIONS
1. Step 1: Prepare 2 test tubes with 0.1M CaCl2, 0.1M Na2C2O4, 0.1M H2C2O4, 6M HCl, and 6M NH40H.
2. Step 2: Drop 5mL 0.1M CaCl2 into each tube.
3. Step 3: Add 1mL 0.1M Na2C2O4 to tube #1. Then, observe the color of tube #1.
4. Step 4: Add 1mL 0.1M H2C2O4 to tube #2. Then, observe the color and compare it with tube #1.
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International University, Vietnam National University - HCMC 3 CHEMISTRY LABORATORY
5. Step 5: Add 10 drops 6M HCl to tube #2. Then, observe the color change of tube #2.
6. Step 6: Then, add 10 drops 6M NH4OH to tube #2. Observe the color change.
5. TEMPERATURE EFFECTS ON EQUILIBRIA
1. Step 1: Fill a test tube with 3mL of 0.1M CoCl2.
2. Step 2: Add conc. HCl drop-by-drop. STOP when the solution turns purple
violet. DO AGAIN if deep blue appears.
3. Step 3: Divide the solution into 3 test tubes. − Tube #1:
• Observe the color change at room temperature condition. − Tube #2:
• At warm (hot water) condition. Observe the color and compare it with tube #1.
• At cool (ice bath) condition. Observe the color and compare it with tube #1. − Tube #3:
• At cool (ice bath) condition. Observe the color and compare it with tube #1
• At warm (hot water) condition. Observe the color and compare it with tube #1. III. Results and discussion
1. ACID/BASE EQUILIBRIA (2 pts)
Equilibrium System: 2CrO 2 + ⇌ 2 4 + 2H (aq) Cr2O7 + H2O(l) Description of Predicted Observation Explanation conditions outcome (0.5 pts) Initial solution (0.5 pts) + Conc. HCl (0.5 pts) + 6 N NaOH Comment: (0.5 pts)
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International University, Vietnam National University - HCMC 4 CHEMISTRY LABORATORY
2. EQUILIBRIA OF ACID/BASE INDICATORS (2 pts)
Equilibrium System: H(MV)(aq) + H ⇌  2O(l) H3O+(aq) + MV (aq) Addition Predicted Observation Explanation outcome (0.375 pts) None (control) (0.375 pts) 6 M HCl (0.375 pts) 6 M NaOH (0.375 pts) 6 M HCl Comment: (0.5 pts)
3. COMPLEX ION FORMATION (2 pts)
Equilibrium System: Fe3+ + SCN ⇌ [Fe(SCN)]2+ Addition Predicted Observation Explanation outcome
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International University, Vietnam National University - HCMC 5 CHEMISTRY LABORATORY None (0.25 pts) (control) 0.01M FeCl3 (0.25 pts) 6M NaOH (0.25 pts) Cold (0.25 pts) Hot (0.25 pts) (0.25 pts) 0.1M AgNO3 Comment: (0.5 pts)
4. EQUILIBRIA OF PRECIPITATION REACTIONS (2 pts)
Equilibrium System: Ca2+(aq) + C 2 ⇌ 2O4 (aq) CaC2O4(s) Predicted Addition Observation Explanation outcome Test tube 1: (0.375 pts) 0.1 M Na2C2O4 Test tube 2: (0.375 pts) + 0.1 M H2C2O4 Test tube 2: (0.375 pts) + 6 M HCl
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International University, Vietnam National University - HCMC 6 CHEMISTRY LABORATORY Test tube 2: (0.375 pts) + 6 M NH4OH Comment: (0.5 pts)
5. TEMPERATURE EFFECTS ON EQUILIBRIA (2 pts)
Equilibrium System:Co(H  ⇌
2O)62+(aq) + 4Cl (aq) CoCl 
42(aq) + 6H2O(l) Description of Predicted Observation Explanation conditions outcome Nothing changed (0.5 pts) (control) (0.5 pts) Hot water bath (0.5 pts) Ice-water bath Comment: (0.5 pts) IV. Conclusions (1 pt)
(conclude all your performance in this report)
The report must be typed and handed in together with the signed data sheet by the deadline