Weigh out accurately 9.99 g of copper(II) sulfate pentahydrate (CuSO4·5H2O) by taring using a clean and dry empty 250-ml beaker. 2. Add tap water to the beaker to reach the 50-mL mark on the side of the beaker. 3. Dissolve all the crystals of CuSO4·5H2O in the water using a clean glass rod for stirring. 4. Then using a glass funnel transfer all the blue solution to a 100-mL volumetric flask. Rinse the beaker with about 10 mL of water and transfer the solution to the volumetric flask. Repeat the rinsing of the beaker with another 10 mL of water and transfer the solution to the volumetric flask. This is called quantitative transfer of the solution. 5. Then add enough water to reach the calibration mark of the volumetric flask. (You will need to use a dropper to add the last few drops of water to ensure the meniscus is on the calibration mark). Close the volumetric flask with a stopper and mix the solution well (so that it is homogeneous). 6. You have now prepared a standard solution (or stock solution) of copper(II) sulfate pentahydrate. Label this solution Solution S. Prepare dilute solutions of copper(II) sulfate pentahydrate from Solution S. You must pipette Solution S from a small beaker. Solution 1: Transfer 15.00 mL of water from a burette to a 50-mL conical flask. Then add 5.00 mL of Solution S with a 5-mL pipette. Mix the solution well. Label this solution Solution 1. Solution 2: Transfer 25.00 mL of Solution S with a 25-mL pipette to a 250-mL volumetric flask. Then add enough water up to the calibration mark. Mix well. Label this solution Solution 2. 1 Solution 3: Transfer 25.00 mL of Solution S with a 25-mL pipette to a 50-mL volumetric flask. Then add enough water up to the calibration mark. Mix well. Label this solution Solution 3. Solution 4: Transfer 25.00 mL of Solution S with a 25-mL pipette to a 100-mL volumetric flask. Then add enough water up to the calibration mark. Mix well. Label this solution Solution 4. Calculations: Determine the molarities of Solutions 1, 2, 3 and 4. Apply the rules of significant figures Solution 1: Solution 2: Solution 3: Solution 4: Transfer the solutions into small vials. The volumes in the vials should be very nearly equal. Then place the vials (containing the solutions) on a white piece of paper next to each other. Look very carefully at the intensity of the colour of each solution. Arrange the solutions S, 1, 2, 3 and 4 in order of decreasing intensity of the colour: ______________________________________________________________________ Is there any relationship between the concentration of each solution and the intensity of the colour of the solution? _____________________ Explain. ______________________________________________________________________ 2 EXERCISE 3: Volumetric Analysis What is the dilution factor that gave the following solutions from Solution S? (i) Solution 1: ____________________________ (ii) Solution 2: ____________________________ What volume of Solution 3 contains 6.022 × 1020 copper(II) ions? Show your calculations below.

Weigh out accurately 9.99 g of copper(II) sulfate pentahydrate (CuSO4·5H2O) by taring using a clean and dry empty 250-ml beaker. 2. Add tap water to the beaker to reach the 50-mL mark on the side of the beaker. 3. Dissolve all the crystals of CuSO4·5H2O in the water using a clean glass rod for stirring. 4. Then using a glass funnel transfer all the blue solution to a 100-mL volumetric flask. Rinse the beaker with about 10 mL of water and transfer the solution to the volumetric flask. Repeat the rinsing of the beaker with another 10 mL of water and transfer the solution to the volumetric flask. This is called quantitative transfer of the solution. 5. Then add enough water to reach the calibration mark of the volumetric flask. (You will need to use a dropper to add the last few drops of water to ensure the meniscus is on the calibration mark). Close the volumetric flask with a stopper and mix the solution well (so that it is homogeneous). 6. You have now prepared a standard solution (or stock solution) of copper(II) sulfate pentahydrate. Label this solution Solution S. Prepare dilute solutions of copper(II) sulfate pentahydrate from Solution S. You must pipette Solution S from a small beaker. Solution 1: Transfer 15.00 mL of water from a burette to a 50-mL conical flask. Then add 5.00 mL of Solution S with a 5-mL pipette. Mix the solution well. Label this solution Solution 1. Solution 2: Transfer 25.00 mL of Solution S with a 25-mL pipette to a 250-mL volumetric flask. Then add enough water up to the calibration mark. Mix well. Label this solution Solution 2. 1 Solution 3: Transfer 25.00 mL of Solution S with a 25-mL pipette to a 50-mL volumetric flask. Then add enough water up to the calibration mark. Mix well. Label this solution Solution 3. Solution 4: Transfer 25.00 mL of Solution S with a 25-mL pipette to a 100-mL volumetric flask. Then add enough water up to the calibration mark. Mix well. Label this solution Solution 4. Calculations: Determine the molarities of Solutions 1, 2, 3 and 4. Apply the rules of significant figures Solution 1: Solution 2: Solution 3: Solution 4: Transfer the solutions into small vials. The volumes in the vials should be very nearly equal. Then place the vials (containing the solutions) on a white piece of paper next to each other. Look very carefully at the intensity of the colour of each solution. Arrange the solutions S, 1, 2, 3 and 4 in order of decreasing intensity of the colour: ____________________________________________________________ Is there any relationship between the concentration of each solution and the intensity of the colour of the solution? _ Explain. ________________________________ 2 EXERCISE 3: Volumetric Analysis What is the dilution factor that gave the following solutions from Solution S? (i) Solution 1: (ii) Solution 2: What volume of Solution 3 contains 6.022 × 1020 copper(II) ions? Show your calculations below.

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter4: Energy And Chemical Reactions

Section: Chapter Questions

Problem 120QRT

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