Chemistry Practical-1 PDF

P a g e | 332 Chemistry Practicals. Experiment #1 :How fitting up a wash bottle prepared? Material Required: Water bottles, Water, Dish soap, Safety goggles, Gloves, Rubber band. Procedure: i. En...

P a g e | 332 Chemistry Practicals. Experiment #1 :How fitting up a wash bottle prepared? Material Required: Water bottles, Water, Dish soap, Safety goggles, Gloves, Rubber band. Procedure: i. Ensure you have the required safety equipment, such as gloves and safety goggles, if handling chemicals. ii. Verify that the wash bottle is clean and dry. iii. Remove the cap or lid. Insert a short piece of glass or plastic tubing into a rubber stopper. iv. Place a funnel into the top of the rubber stopper. Insert the rubber stopper with the tubing into the neck of the wash bottle. v. Create a tight seal around the neck of the wash bottle using a grommet or rubber washer. vi. Attach one end of the rubber or plastic tubing to the tubing in the rubber stopper. Secure the wash bottle to a lab stand or ring stand to prevent tipping. vii. If necessary, gently heat the wash bottle using a hot plate or heat source. Use the funnel to pour the desired liquid into the wash bottle. viii. Dispense the liquid by gently squeezing the wash bottle. ix. Test the wash bottle to ensure it dispenses the liquid correctly and adjust the tubing or nozzle if needed. x. Label the wash bottle with the contents and safety information. Store the wash bottle in a safe location, away from direct sunlight or heat sources.  P a g e | 333 Experiment # 2: To pacify the given sample of imposed naphthalene crystallization. Material Required: Beaker, Funnel, Filter paper, Burner, Tripod stand, Wire gauze, Stirrer, Thermometer. Chemicals Required: Distilled water, Given the mixture of impure naphthalene and phosphoric acid. Procedure: i. Ensure safety gear (gloves, goggles) is worn and work in a well-ventilated area. ii. Weigh the impure naphthalene sample accurately and record the initial mass. Place the impure naphthalene in a beaker. iii. Add a non-polar solvent (e.g., petroleum ether) to dissolve the impurities while keeping naphthalene in solution. iv. Heat and stir gently. v. Set up a filtration apparatus with filter paper or a Büchner funnel and filter flask. vi. Filter the hot solution to remove insoluble impurities. vii. Transfer the clear naphthalene solution to a dish. Allow the solution to cool slowly, facilitating crystallization. viii. Collect the naphthalene crystals and drain off any remaining liquid. Air-dry the crystals completely. ix. Weigh the dried crystals accurately and record the final mass. x. Calculate the percentage yield and purity of the purified naphthalene. xi. Dispose of waste materials properly and clean glassware and equipment. 𝑻𝒉𝒆𝒐𝒓𝒆𝒕𝒊𝒄𝒂𝒍 𝒀𝒊𝒆𝒍𝒅 𝑷𝒆𝒓𝒄𝒆𝒏𝒕𝒂𝒈𝒆 𝒀𝒊𝒆𝒍𝒅 = × 𝟏𝟎𝟎% 𝑨𝒄𝒕𝒖𝒂𝒍 𝒀𝒊𝒆𝒍𝒅 𝑻𝒐𝒕𝒂𝒍 𝑴𝒂𝒔𝒔 𝒐𝒇 𝒕𝒉𝒆 𝑶𝒃𝒕𝒂𝒊𝒏𝒆𝒅 𝑪𝒓𝒚𝒔𝒕𝒂𝒍𝒔 𝑷𝒖𝒓𝒊𝒕𝒚 = × 𝟏𝟎𝟎% 𝑨𝒄𝒕𝒖𝒂𝒍 𝑴𝒂𝒔𝒔 𝒐𝒇 𝑷𝒖𝒓𝒊𝒇𝒊𝒆𝒅 𝑵𝒂𝒑𝒉𝒕𝒉𝒂𝒍𝒆𝒏𝒆 xii. By following these steps and calculations, you can determine both the percentage yield and the purity of the purified naphthalene obtained in your experiment. xiii. Weigh the dried naphthalene crystals accurately, and record this value as the "Actual Yield." xiv. Calculate the theoretical yield by assuming 100% purity of the impure sample. xv. If you had "X" grams of impure naphthalene initially, then the theoretical yield would be "X" grams. Use the values from step 1 and step 2 to calculate the percentage yield using the formula mentioned earlier. xvi. To calculate the purity, you need to know the mass of the impurities in the obtained crystals.  P a g e | 334 xvii. If you don't have this information, you can conduct further testing or analysis to determine the purity more accurately. However, the purity calculation is typically done by analyzing the product using techniques like spectroscopy or chromatography. xviii. Once you have the mass of the impurities, use the formula for purity to determine the purity of the purified naphthalene.  P a g e | 335 Experiment # 3: Separate Naphthalene from the given mixture of sand and naphthalene by sublimation. Material Required: Evaporating dish, burner, funnel, filter paper, cotton, tripod stand, sand bath Chemicals Required: Given mixture of sand and naphthalene. Procedure: i. Take about 5g of the mixture on a China dish and place it on the sand bath. ii. Fold filter paper in a cone shape and moisten the inner side of the paper with distilled water. Place the filter paper on the funnel. iii. Close the open end of the funnel’s stem with cotton. iv. Invert the funnel on the China dish so that the vapors of the given mixture don’t escape the system. v. Heat the sand bath for 5-10 minutes by using the burner. vi. Now, carefully lift the funnel, and remove the filter paper out of the funnel. vii. Observe the crystals of pure naphthalene stuck on filter paper. Result: Given organic compound (Naphthalene) is separated from the mixture.  P a g e | 336 Experiment #4: Determine the melting point of the given compound (Naphthalene). Material Required: Thermometer, Beaker, Thread, Capillary tube, Tripod stand, wire guaze, Stand with clamp. Chemicals Required: Water and given compound (Naphthalene) Procedure: i. Take a capillary tube and close its one end by heating the end in the flame for 2-3 minutes while continuously rotating it. ii. Take naphthalene on a tile and crush it into a fine powder. iii. Stuff some naphthalene into the capillary tube and strap a thermometer to it. iv. Immerse the capillary tube in a hot water bath. v. As the temperature of water rises, at a particular temperature the naphthalene melts out of the capillary tube. vi. Make note of the temperature (t1) as soon as the compound begins to melt. vii. Make note of the temperature (t2) as soon as the compound is melted completely. viii. The average of the two readings gives the correct melting point of the substance. Observations: No of observations Melting point in °C 1 2 Mean value=T1+T2/2 Result: The melting point of the given organic compound is ______°C.  P a g e | 337 Experiment # 5: Determine the Boiling point of the given compound (Acetone). Material Required: Thermometer, Beaker, Thread, Fusion tube, Tripod stand, wire guaze, Stand with clamp and stirrer. Chemicals Required: Water and given compound (Acetone) Procedure: i. Close one end of the capillary tube by gently heating on oxidizing flame. ii. Attach the fusion tube with the thermometer by using thread in such a way that the bulb of the thermometer and base of the fusion tube are at the same level. iii. Hang the thermometer along with the fusion tube using thread with the clamp of the stand. iv. Take 250 cm3 beaker and add approximately 100 cm3 of water in it, place this beaker on tripod stand over the wire guaze. v. Now dip the thermometer along with the fusion tube onto the beaker of water. vi. Fill one-third of the fusion tube with Acetone with the help of dropper. vii. Heat the beaker with continuous stirrer. viii. Note the temperature at which continuous steam of bubbles start to come out. Observations: No of observations Boiling point in °C 1 2 Mean value=T1+T2/2 Result: The Boiling point of the given organic compound is ______°C  P a g e | 338 Experiment# 6: Prepare 100cm3 of 0.1M sodium hydroxide (NaOH) solution. Material Required: Top loading balance, Beaker, Measuring flask with stopper, Funnel, Spatula, watch glass. Chemicals Required: Distill Water and solid NaOH. Procedure: First calculate the mass of NaOH required to make 0.1M NaOH solution. Molar mass of NaOH = 23+16+1 = 40 g/mol 100 Volume of NaOH required in dm3 = 1000 x1dm30 = 0.1 dm3 No pf moles of NaOH required = molarity of NaOH required x Volume of NaOH required in dm3 = o.1 x 0.1 = 0.01 mol Mass of NaOH required in g = moles of NaOH x Molar Mass = 0.01 x 40 = 0.4 g Set the top loading balance at 0.00g. Place dry watch glass on top loading balance and tare the reading. Now weigh 0.4g NaOH on the watch glass by using a spatula. Transfer NaOH into the beaker, wash the watch glass with distilled water, and transfer it to the beaker.  P a g e | 339 Now add about 20 cm3 of water in beaker and stir the solution so NaOH dissolve in distill water completely. Transfer the solution into measuring flask (100cm3) with the help of funnel. Add more water to raise the level of the solution below the mark of measuring flask. Now add distill water carefully with the help of dropper till the lower meniscus of the solution. Close the measuring flask and turn it upside down to ensure the solution is thoroughly mixed.  P a g e | 340 Experiment # 7: To prepare a standard solution of oxalic acid and with its help standardize a solution of NaOH. Material Required: Top loading balance, Beaker, measuring flask with stopper, Funnel, Spatula, watch glass, Burette, pipette, Measuring cylinder. Chemicals Required: Distill Water and solid Oxalic Acid, 0.1M NaOH solution, 2-3 drops of phenolphthalein indicator. Principle: Acid-Base Titration. Indicator: Phenolphthalein End-point: colorless to light pink Chemicals Reaction: Mole Ratio: 1:2 Preparing the Standard Solution of Oxalic Acid: i. Measure approximately 4 grams of oxalic acid dihydrate (H2C2O4·2H2O) using an analytical balance. ii. Record the exact mass. iii. Dissolve the measured oxalic acid in about 300 mL of deionized or distilled water in a clean beaker. iv. Stir the solution until all the oxalic acid has dissolved. v. This solution contains approximately 0.1 M (mol/L) of oxalic acid. vi. Carefully transfer the oxalic acid solution to a clean, dry, 500 mL volumetric flask using a funnel. vii. Rinse the beaker with deionized water and add the rinsings to the flask. viii. Fill the flask up to the mark with deionized or distilled water. Mix the solution thoroughly by inverting the flask several times. This is your standard solution of oxalic acid. ix. Standardizing the Sodium Hydroxide (NaOH) Solution:  P a g e | 341 x. Rinse a burette with a small amount of the sodium hydroxide solution. xi. Then, fill the burette with the sodium hydroxide solution. xii. Use a pipette to measure exactly 10 mL of the prepared standard oxalic acid solution and transfer it to a clean conical flask. xiii. Add a few drops of phenolphthalein indicator to the flask. xiv. The solution should turn colorless. xv. Place the flask under the burette, and titrate the oxalic acid solution by slowly adding sodium hydroxide solution drop by drop while swirling the flask continuously. xvi. Continue adding the NaOH solution until the color changes from colorless to a pale pink that persists for at least 30 seconds. xvii. This indicates that all the oxalic acid has reacted with the sodium hydroxide. xviii. Record the volume of sodium hydroxide solution used from the burette. xix. This volume represents the amount of NaOH required to neutralize the known amount of oxalic acid. Observations: No. of Obs. Initial reading Final Reading Mean 1 0 10 10cm3 2 10 20 10 cm3 3 20 30 10 cm3 Mean volume= 10 cm3 Calculations: Given : Required Oxalic acid : NaOH M1V1 / n1 = M2V2 / n1 M1 = M2V2n1 / V1n2 M1 = 0.1 X 10 x 1 / 10 x2 =0.05M Result: The molarity of the given solution is _______  P a g e | 342 Experiment # 8: To prepare approximated N/10 solution of H2SO4 determine its exact normality by titrating it against standard N/10 NaoH. Material Required: Top loading balance, Beaker, measuring flask with stopper, Funnel, Spatula, watch glass, Burette, pipette, Measuring cylinder. Chemicals Required: Distill Water and 0.1M H2SO4, 0.1M NaOH solution, 2-3 drops of phenolphthalein indicator. Principle: Acid-Base Titration. Indicator: Phenolphthalein End-point: Light pink to colorless. Chemicals Reaction: Mole ratio: 2:1 Procedure: i. Pipette out 10mL of the 0.1M NaOH and transfer it into a clean conical flask. ii. Add 1-2 drops of phenolphthalein indicator solutions turns purple. iii. Take oxalic acid in burette and note the initial reading. iv. Add oxalic acid dropwise from the burette into titrating flask. v. Titrate it with 0.1N Sulphuric acid solution until colour changes from purple to colorless. vi. Difference between the two readings give the volume of acetic acid used. vii. Repeat the experiment to get three concordant readings. No. of Obs. Initial reading Final Reading Mean 1 0 10 10cm3 2 10 20 10 cm3  P a g e | 343 3 20 30 10 cm3 Mean volume= 10 cm3 Calculations: Given : Required H2SO4 : NaOH M1V1 / n1 = M2V2 / n1 M1 = M2V2n1 / V1n2 M1 = 0.1 X 10 / 10 x2 =0.05M Result: The normality/molarity of the given solution is _______ Precautions: Wash the watch glass carefully so that even a single crystal is not left on the watch glass. Bring the watch glass close to the funnel while transferring the weighed substance and transfer it gently. Wash it repeatedly with distilled water. Wash the burette with water after titration is over. The last few drops should be added using a pipette to avoid the extra addition of distilled water above the mark on the neck of the measuring cylinder.  P a g e | 344 Experiment# 9: Determine the amount of acetic acid in the 100cm3 of vinegar sample. Principle: Acid-Base Titration. Indicator: Phenolphthalein End-point: Light pink to colourless. Standard solution: 0.05 M NaOH Chemical Equation: Procedure: 1. Take 5cm3 of vinegar in 100 cm3 measuring flask and dilute upto mark with distilled water, shake it well. 2. Pipette out 10cm3 of NaOH solution into titration flask. 3. Add a drop of indicator. 4. Take vinegar (Acetic acid) in burette and note the initial reading. 5. Add acetic acid drop wise from the burette into conical flask. 6. Keep on titration NaOH solution with acetic acid until light pink colour appear. 7. Difference between the two readings give the volume of acetic acid used. 8. Repeat the experiment to get three concordant readings. Observations: No. of Obs. Initial reading Final Reading Mean 1 0 10 10cm3 2 10 20 10 cm3 3 20 30 10 cm3 Mean volume= 10 cm3  P a g e | 345 Calculations: Given : Required Acetic acid : NaOH M1V1 / n1 = M2V2 / n1 M1 = M2V2n1 / V1n2 M1 = 0.05 X 10 x1/ 10 x1 =0.05M Strength of Acetic Acid = molarity x mol. Weight = 0.05 x 60 = 3.0 g/ dm3 1000cm3 of vinegar contains Acetic acid = 3.0g 100cm3 of vinegar contains Acetic acid = 3 x 100 / 1000 = 0.3g 5cm3 of vinegar contains Acetic acid = 0.3g 100cm3 of vinegar contains Acetic acid = (0.3 x 100) 5 = 6g Result:  P a g e | 346 Experiment # 10: Standardize the given solution of KMNO4 volumetrically. Calculate the volume of KMNO4 required to prepare 1.0 dm3 of 0.01M KMNO4 solution. Principle: Oxidation- Reduction Titration. Indicator: KMNO4 Itself Endpoint: Light pink to colourless. Standard solution: 0.1 M FeSO4 Chemical Equation: 2KMnO4+3H2SO4 → K2SO4+2MnSO4+ 3H2O+5 (O) [2FeSO4+H2SO4+O → Fe2(SO4)3+H2O]x5 ---------------------------------------------------------------------------------- 2KMnO4+ 8H2SO4 + 10FeSO4 → 5Fe2(SO4)3+K2SO4+2MnSO4+8H20 Procedure: 1. Pipette out 10cm3 of FeSO4 solution into conical flask. 2. Add half test tube of dilute H2SO4 into the flask. 3. Take KMNO4 solution in burette and note the initial reading. 4. Add KMNO4 solution drop wise from the burette into conical flask. 5. Keep on titration FeSO4 solution with KMNO4 solution until light pink colour appears. 6. Difference between the two readings give the volume of acetic acid used. 7. Repeat the experiment to get three concordant readings. Observations: No. of Obs. Initial reading Final Reading Mean 1 0 10 10cm3  P a g e | 347 2 10 20 10 cm3 3 20 30 10 cm3 Mean volume= 10 cm3 Calculations: Given: Required KMNO4 : FeSO4 M1V1 / n1 = M2V2 / n1 M1 = M2V2n1 / V1n2 M1 = 0.1 X 10 x2 / 10 x10 =0.02M Given: Required KMNO4 : KMNO4 M1V1 = M2V2 0.02XV1 =0.01X1000 V1 = 0.01 X 1000 / 0.02 = 500cm3