Materials Included In Kit

Additional Materials Required

Safety Precautions

Copper(II) sulfate is moderately toxic by ingestion and inhalation and is a skin and respiratory irritant. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Please review current Safety Data Sheets for additional safety, handling and disposal information.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulation that may apply, before proceeding. Dispose of all solutions down the drain with an excess of water according to Flinn Suggested Disposal Method #26b.

Lab Hints

• Enough materials are provided in this Super Value Kit for 5 classes of 30 students each, working in pairs (75 total student groups). All test tubes included are completely reusable. This laboratory activity may reasonably be completed in one 50-minute class period. The pre-laboratory assignment may be completed before coming to lab and the data compilation and questions may be completed the day after the lab.

Teacher Tips

• Enough copper(II) sulfate is provided to make several extra solutions. It is recommended that you demonstrate to your students how to properly prepare a solution before they begin lab.
• Volumetric flasks are the best piece of glassware in which to prepare a solution. However, because they are so expensive, they may not be available for each student group. If you have just a few volumetric flasks, it is recommended that your students follow Part A for preparing the stock solution. Have them take turns using the flask. Once their solution is prepared, have them transfer it to a labeled bottle and pass the volumetric flask on to the next group. If there are not enough volumetric flasks available to share among the class, follow Part B for preparing the solution in a calibrated beaker.
• Volumetric pipets are the preferred equipment for preparing dilutions. However, because these are also expensive, they may not be available for each student group. If volumetric pipets are available, it is recommended that your students alter the procedure in Parts C and D and use volumetric pipets to measure volumes instead of a 10-mL graduated cylinder. Because the pipets would be needed throughout the entire lab, they cannot be shared efficiently. Therefore, a classroom supply is needed to use pipets in Parts C and D.
• To follow proper lab technique, the pipets should be rinsed with the solution being transferred three times before actually transferring any solution. Because only 10 mL of solution are being prepared, the instructions do not call for this. However, if you would like to teach your students this procedure, please add instructions on the board and demonstrate proper transferring technique prior to lab.
• The copper(II) sulfate crystals are fairly large crystals and therefore may take a while to dissolve. To speed up the dissolving process, stir vigorously or grind the crystals in a mortar and pestle. A single crystal may also weigh more than necessary to prepare 100 mL of a 0.10 M solution. Again, grinding the crystals into smaller pieces will fix this situation.

Answers to Prelab Questions

1. Calculate the number of grams of copper(II) sulfate pentahydrate, CuSO₄•5H₂O, required to prepare 100 mL of a 0.10 M copper(II) sulfate solution. Remember to include the 5H₂O when determining the molecular weight. Show all work. Describe how this solution will be prepared in the lab.

   Use steps 1 and 2 from the Background section.

   {12032_Answers_Table_1}

   Detailed instructions for solution preparation are actually provided in the Procedure section (Part A if volumetric flasks are available, Part B if they are not). An overview of the solution preparation is: add 2.5 g of CuSO₄•5H₂O to enough distilled or deionized water to prepare a total of 100 mL of solution.

2. Calculate the number of milliliters of 0.10 M copper(II) sulfate solution that must be diluted to prepare 10 mL of a 0.050 M copper(II) sulfate solution. Show all work. Write a step-by-step procedure for preparing this solution that you can follow in lab (see the Background section and Part D in the Procedure section for guidance).

   Use Equation 6 from the Background section to calculate the number of mL required. The procedure students should describe should be similar to steps 24 and 25 in Part D of the Procedure section.

   {12032_PreLab_Equation_8}
3. Calculate the number of milliliters of 0.10 M copper(II) sulfate solution that must be diluted to prepare 10 mL of a 0.015 M copper(II) sulfate solution. Show all work. Write a step-by-step procedure for preparing this solution that you can follow in lab (see the Background section and Part D in the Procedure section for guidance).

   Use Equation 8 from the Background section to calculate the number of mL required. The procedure students should describe should be similar to steps 24 and 25 in Part D of the Procedure section.

   {12032_PreLab_Equation_9}

Sample Data

Data Table 1. Preparing Serial Dilutions

Data Table 2. Preparing Dilutions of a Given Molarity Data Analysis

1. Calculate the concentrations of each of the serial dilutions in Data Table 1 by rearranging equation 4 from the Background section. Show all work. Fill in the cells in Data Table 1.

   Use the following equation for each calculation:

   {12032_Data_Equation_10}
   {12032_Data_Table_3}
2. Compare the concentrations of each of the serial dilutions to the color ranking. What is the relationship between concentration and color intensity (depth of color)?

   The color intensity decreases with concentration. As the concentration decreases, the solutions will begin to appear clear instead of blue. Any trace of blue can usually be observed in the meniscus. However, students may have a hard time ranking the very dilute solutions in terms of color intensity.

3. Calculate the concentrations of the dilutions in test tubes 2 and 3 in Data Table 2 using equation 4 from the Background section. Show all work. Fill in all of the other empty cells in the Data Table 2 with the values from the Prelab Questions.

   The calculations for tubes 4 and 5 are in the Prelab Questions answers.
   Calculate the concentrations in tubes 2 and 3 using

   {12032_Data_Equation_10}
   {12032_Data_Table_4}
4. Compare the concentrations of each of the dilutions in Data Table 2 to the color ranking. What is the relationship between concentration and color intensity (depth of color)?

   The color intensity decreases with concentration.

Answers to Questions

1. Calculate the number of grams of potassium iodide, KI, needed to prepare 500 mL of a 0.250 M solution. Show all work.

   Use steps 1 and 2 from the Background section.

   {12032_Answers_Table_5}
2. Calculate the molarity of a solution prepared by dissolving 25 g of magnesium sulfate, MgSO₄, in enough water to make a solution with a total volume of 100 mL. Show all work.

   Follow steps 1 and 2 from the Background section, but use step 2 first, then step 1.

   {12032_Answers_Table_6}
3. Nitric acid solutions with a pH of about 5 are often used to simulate acid rain. A nitric acid solution with a pH of 5 has a concentration of 0.00001 M. Describe how to prepare 10 mL of a 0.00001 M solution using a 1 M stock solution and the serial dilution technique. Draw a diagram if helpful.

   Perform a serial dilution such as that outlined in Part C of the Procedure section. A total of 6 test tubes would be needed. The 1 M stock solution would be placed in the first test tube. Then 1 mL from that test tube would be transferred to the second tube along with 9 mL of water. The procedure would continue down the row of test tubes. The following diagram outlines the procedure.

   {12032_Answers_Figure_2}
4. Describe how to prepare 100 mL of a 0.025 M sodium phosphate, Na₃PO₄, solution by diluting a 0.60 M stock solution. Show all work.

   Equation 5 is used first to calculate that 4.2 mL of 0.60 M stock solution is needed. To prepare the solution, 4.2 mL of stock sodium phosphate solution would be precisely measured out and diluted to exactly 100 mL.

   {12032_Answers_Equation_11}
5. Consider a dilution where 25 mL of a 0.50 M sodium hydroxide solution was diluted to a total volume of 100 mL. What is the concentration of the diluted solution? Show all work.

   Equation 4 is rearranged and used to calculate a concentration of 0.13 M.

   {12032_Answers_Equation_12}

References

Griswold, N. E.; Neidig, H. A.; Spencer, J. N.; Stanitski, C. Laboratory Handbook for General Chemistry; Chemical Education Resources: Palmyra, PA, 1996; pp 23–24.

Introduction

Solutions are an important part of chemistry. But how are accurate concentrations of solutions prepared? In this laboratory activity, a copper(II) sulfate solution will first be prepared, then diluted to prepare several other solutions with different concentrations.

Concepts

• Solutions
• Concentration
• Molarity
• Dilutions

Background

Preparing Solutions

The amount of solute that is dissolved in a given quantity of solvent is expressed as the concentration of the solution. A dilute solution contains only a small amount of solute in a given amount of solution, while a concentrated solution contains a large amount of solute in a given amount of solution. The units most commonly used to describe the concentration of solutions are molarity units. The molarity, M, of a solution is the number of moles of solute in one liter of solution. To determine the molarity of a solution, the following equation can be used:

Used in conjunction with the molecular weight, MW, of a solute, Equation 1 is used to determine the number of grams of solute needed to prepare a given volume of a solution with a specific concentration. For example, consider the preparation of 500 mL of a 0.80 M solution of sodium chloride, NaCl. The steps below outline this procedure.

Step 1—Determine the number of moles necessary to prepare this solution. To do this, rearrange equation 1 to solve for moles.

moles of NaCl = 0.40 moles

Therefore, distilled or deionized water must be added to 0.40 moles of NaCl and the resulting solution diluted to a total volume of 500 mL to prepare a 0.80 M solution.

Step 2—Convert the number of moles to grams using the molecular weight. Therefore, 23 g of NaCl is required to prepare 500 mL of a 0.80 M sodium chloride solution.

Once the calculations have been done to determine how much solute is needed to correctly prepare the solution, precise analytical techniques must be followed when actually making the solution. The steps below outline proper solution preparation procedures.

Step 3—Obtain a piece of volumetric glassware calibrated to the volume needed. Volumetric glassware is glassware that has been calibrated (and marked) to hold a specific volume. The most common form of volumetric glassware used for preparing solutions is the volumetric flask, a flask that has a long, narrow neck with a marking on it. For a 100-mL volumetric flask, the mark on the neck indicates that when filled to the mark, the flask will contain exactly 100 mL. Because volumetric flasks are expensive, they may not be available for every student lab group. However, solutions are not commonly stored in volumetric flasks, so only a few volumetric flasks are necessary for an entire class to prepare solutions. One group can prepare a solution, then empty the solution into a labeled storage bottle and pass the volumetric flask on to another group. If no volumetric glassware is available for preparing solutions, the glassware must be calibrated before preparing the solution. To calibrate a piece of glassware, a specified volume is poured into the container and the liquid level marked.

Step 4—Precisely weigh out the required number of grams (determined in Step 2) of solid on a balance in a weighing dish. Transfer the solid to a clean, dry beaker (with a larger capacity than the necessary volumetric flask). There may be a few grains of solid left on the weighing dish, so use a wash bottle filled with distilled or deionized water to rinse any remaining solid from the weighing dish into the beaker. Rinse the weighing dish several times to make sure that all of the solid was transferred. This process of transferring every bit of the solid is called quantitatively transferring. The rinse water may be enough water to dissolve all of the solid in the beaker. If it is not, add a minimum amount of distilled or deionized water to dissolve any remaining solid.

Step 5—Using a funnel, transfer the solution in the beaker to the volumetric flask. Rinse the beaker with a small amount of distilled or deionized water, transferring the rinse water through the funnel into the volumetric flask. Rinse from the beaker through the funnel into the flask several times to thoroughly rinse the beaker and the funnel.

Step 6—Fill the volumetric flask with distilled or deionized water. When the flask is about one-half to two-thirds full, cap the flask and invert it several times to make sure the solution is homogeneous. Continue filling the flask until the liquid level is almost at the mark. Fill to the mark with a pipet or wash bottle containing distilled or deionized water drop-by-drop until the bottom of the meniscus is directly on the mark. Again cap the flask and invert it several times to thoroughly mix the solution. Solutions are not generally stored in volumetric flasks, so transfer the solution to a labeled bottle and cap the bottle to prevent evaporation or contamination.

Diluting Solutions

Experiments often require a solution that is more dilute than what is on hand in the stockroom. In this case, a more concentrated stock solution is diluted to obtain the desired concentration. To carry out a dilution, the following equation is used:

Molarity_{concentrated soln} x volume_{concentrated soln} = Molarity_{dilute soln} x volume_{dilute soln}

In this equation, Molarity_{concentrated soln} is the concentration of the stock solution, volume_{concentrated soln} is the volume of the stock solution required to prepare the dilute solution, Molarity_{dilute soln} is the concentration of the dilute solution, and volume_{dilute soln} is the volume of the dilute solution needed. The equation is commonly written with a 1 in place of concentrated soln, a 2 in place of dilute soln, and the multiplication signs are eliminated.

M₁ V₁ = M₂ V₂

For example, assume that the 0.80 M sodium chloride solution prepared in the example above is in the stockroom, but for another experiment, 100 mL of a 0.20 M sodium chloride solution is needed. The 0.20 M solution is prepared by diluting the 0.80 M solution. In a dilution, M₁, M₂, and V₂ from equation 6 are generally known. Equation 6 is rearranged to solve for the unknown V₁. The known values are substituted into Equation 5 to solve for the volume of the concentrated solution required to prepare the dilute solution. But how are these values used to actually prepare the new solution? First, 25 mL of the stock 0.80 M sodium chloride solution must be measured. This can be done in several ways depending on the equipment available in the laboratory. One common method involves using a graduated cylinder. For greatest accuracy always use the smallest graduated cylinder that will contain the necessary volume. In this example, a clean, dry 100-mL graduated cylinder would work well. Using a Beral-type pipet, transfer 25 mL of the 0.80 M solution to the graduated cylinder, taking care not to get any droplets of liquid on the sides of the cylinder. Fill the graduated cylinder so that the bottom of the meniscus is exactly at the 25-mL mark. Then fill the remainder of the cylinder with distilled or deionized water using a wash bottle. When the level of the solution is almost at the 100-mL mark, stir the solution to ensure it is homogeneous. Finish filling the cylinder to the 100-mL mark with water from the wash bottle until the bottom of the meniscus is exactly at the 100-mL mark. Again stir the solution to thoroughly mix it. At this point, 100 mL of a 0.20 M sodium chloride solution has been accurately prepared and can be used in the new experiment. The solution should not be stored in the graduated cylinder, however. Instead, transfer it to a labeled bottle and cap the bottle to prevent evaporation or contamination.

The above example is merely one kind of dilution that may be needed. A serial dilution is a dilution where a series of solutions are prepared, each one 1⁄10 as concentrated as the previous one. To prepare serial dilutions, 1 mL of the stock solution is diluted with 9 mL of water. Then 1 mL of this solution is diluted with 9 mL of water. This process is repeated until the desired concentration has been reached. Equation 4 can be used to calculate the concentration of the more dilute solution; however, because each solution is 1⁄10 as concentrated, the concentrations can simply be divided by 10 down the line. For example, if a serial dilution was performed on the 0.80 M sodium chloride solution above, the first dilution would be 0.080 M, the second 0.0080 M, the third 0.00080 M, and so on. Serial dilutions are commonly used in microbiology where the solution being diluted contains bacterial colonies. It is important that the number of colonies growing in the solution not be too large, so bacterial solutions are commonly diluted down to concentrations 1,000,000 (10⁶) times more dilute than the original solution!

Materials

Prelab Questions

1. Calculate the number of grams of copper(II) sulfate pentahydrate, CuSO₄•5H₂O, required to prepare 100 mL of a 0.10 M copper(II) sulfate solution. Remember to include the 5H₂O when determining the molecular weight. Show all work. Describe how this solution will be prepared in the lab.
2. Calculate the number of milliliters of 0.10 M copper(II) sulfate solution that must be diluted to prepare 10 mL of a 0.050 M copper(II) sulfate solution. Show all work. Write a step-by-step procedure for preparing this solution that you can follow in lab (see the Background section and Part D in the Procedure section for guidance).
3. Calculate the number of milliliters of 0.10 M copper(II) sulfate solution that must be diluted to prepare 10 mL of a 0.015 M copper(II) sulfate solution. Show all work. Write a step-by-step procedure for preparing this solution that you can follow in lab (see the Background section and Part D in the Procedure section for guidance).

Safety Precautions

Copper(II) sulfate is moderately toxic by ingestion and inhalation and is a skin and respiratory irritant. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Please review current Safety Data Sheets for additional safety, handling and disposal information.

Procedure

Note: If a volumetric flask is not available, skip Part A and proceed directly to Part B. If a volumetric flask is available, proceed with Part A, then skip to Part C.

Part A. Preparing a 0.10 M Copper(II) Sulfate Solution in a 100-mL Volumetric Flask

1. Check your calculation from Prelab Question 1 for the number of grams of copper(II) sulfate pentahydrate, CuSO₄•5H₂O, required to prepare 100 mL of a 0.10 M solution with your instructor. Once your calculation has been approved, weigh out the required amount of copper(II) sulfate on a balance in a clean, dry weighing dish.
2. Transfer the solid to a clean, dry beaker. Use a wash bottle filled with distilled or deionized water to rinse any remaining solid from the weighing dish into the beaker. Dissolve the solid in the beaker in a minimum amount of distilled or deionized water. Transfer the solution to a 100-mL volumetric flask using a funnel. Rinse the beaker with distilled or deionized water using a wash bottle. Pour the rinse water through the funnel and into the volumetric flask so that every bit of solid copper(II) sulfate or solution is transferred to the volumetric flask. Rinse the beaker, running the rinse water through the funnel several times to thoroughly rinse both the beaker and the funnel.
3. Slowly continue adding distilled or deionized water to the volumetric flask until the flask is one-half to two-thirds full. Place the cap on the volumetric flask and invert it several times to mix the solution. Continue filling the flask until the liquid level is almost to the 100-mL mark. Fill to the mark with a pipet or wash bottle drop-by-drop so that no water splashes up on the sides of the flask. Fill until the bottom of the meniscus is exactly at the 100-mL mark.
4. Cap the volumetric flask and invert it 10–15 times to make a completely homogeneous solution.
5. Once the solution is thoroughly mixed, transfer it to a labeled bottle. Cap the bottle to prevent evaporation or contamination of the solution. This is the 0.10 M stock copper(II) sulfate solution.

Part B. Preparing a 0.10 M Copper(II) Sulfate Solution in a Beaker

6. First, a beaker will need to be calibrated to contain 100 mL of water. Fill a 100-mL graduated cylinder exactly to the 100-mL mark with water. Be sure the meniscus is exactly at the 100-mL mark. Pour this water into a 150-mL beaker. Compare the water level to the 100-mL mark on the beaker. Are they the same? If so, proceed to step 7. If not, with a wax pencil or piece of labeling tape, make a mark on the beaker indicating the level equal to 100-mL of water. If using labeling tape, place the tape so that the bottom edge of the tape marks the level of the water. Be sure to set the beaker on the table so that the water level is even. Make as precise a marking as possible. This beaker is now your calibrated beaker. Empty the beaker and dry it thoroughly.
7. Check your calculation from the Prelab Question 1 for the number of grams of copper(II) sulfate pentahydrate, CuSO₄•5H₂O, required to prepare 100 mL of a 0.10 M solution with your instructor. Once your calculation has been approved, weigh out the required amount of copper(II) sulfate on a balance in a weighing dish. Transfer the solid from the weighing dish into the calibrated beaker.
8. Use a wash bottle filled with distilled or deionized water to rinse any remaining solid from the weighing dish into the beaker. Dissolve the solid in the calibrated beaker in a minimum amount of distilled or deionized water. Rinse the sides of the beaker with distilled or deionized water using a wash bottle to remove any grains of solid copper(II) sulfate or drops of solution that may be adhering to the sides of the beaker.
9. Slowly continue adding distilled or deionized water to the beaker until the water level is almost at the 100-mL mark. Stir the solution and make sure that all of the solid is dissolved. Continue adding water to approach the 100-mL mark, this time adding the water drop-by-drop with a pipet or wash bottle so that no water splashes up on the sides of the beaker. Fill until the water level is exactly at the 100-mL mark.
10. Stir to make a completely homogeneous solution.
11. Once the solution is thoroughly mixed, transfer it to a labeled bottle. Cap the bottle to prevent evaporation or contamination of the solution. This is the 0.10 M stock copper(II) sulfate solution.

Part C. Preparing Serial Dilutions

12. Place five clean, dry test tubes in a test tube rack. Label the tubes 1–5.
13. Fill a 250-mL beaker about half-full with distilled or deionized water. This water will be used to rinse the pipet after each use. This will ensure that the pipet is clean and is not a cause of contamination. This beaker will be called the “rinse beaker.”
14. Label one of the pipets “CuSO₄” with a marker by writing directly on the bulb. Label the second pipet “water.”
15. Using the CuSO₄ pipet, fill a 10-mL graduated cylinder to the 10-mL mark with the stock 0.10 M copper(II) sulfate solution. Make sure that the bottom of the meniscus is exactly at the 10-mL mark. Transfer this solution to the first test tube. Record the necessary data in Data Table 1 for test tube 1. Rinse the graduated cylinder with water and thoroughly dry it with a paper towel.
16. Rinse the CuSO₄ pipet three times, each time filling the pipet with water from the rinse beaker, then emptying the pipet into the sink. Empty as much of the water as possible so that the pipet is as dry as possible for the next use. Use this procedure for rinsing the pipet throughout the remainder of the lab.
17. Using the CuSO₄ pipet, fill the 10-mL graduated cylinder exactly to the 1-mL mark with the solution in test tube 1. Try not to get any drops of solution on the sides of the cylinder. Make sure that the bottom of the meniscus is exactly at the 1-mL mark. If any solution remains in the pipet after filling to the 1-mL mark, empty it back into the first test tube. Use the water pipet to fill the graduated cylinder to the 10-mL mark with distilled or deionized water. Make sure that the bottom of the meniscus is exactly at the 10-mL mark.
18. The solution in the graduated cylinder needs to be mixed before transferring it to test tube 2. To do this, rinse the CuSO₄ pipet according to Step 16, then fill it with the solution in the graduated cylinder. Empty the pipet back into the graduated cylinder, then fill and empty again. The agitation caused by filling and emptying the pipet mixes the solution, making it homogeneous. Transfer the mixed solution to test tube 2 (see Figure 1). Rinse the graduated cylinder with water and thoroughly dry it with a paper towel. Rinse the CuSO₄ pipet according to step 16.
    {12032_Procedure_Figure_1}
19. Record the necessary data in Data Table 1 for test tube 2.
20. Repeat steps 17–18, filling the third test tube with 1 mL of solution from the second test tube plus 9 mL of water, then filling the fourth test tube with 1 mL of solution from the third test tube plus 9 mL of water, and finally filling the fifth test tube with 1 mL of solution from the fourth test tube plus 9 mL of water (see Figure 1). Record the necessary data in Data Table 1 for test tubes 3–5.
21. Compare the color of the stock solution and each of the dilutions in test tubes 1–5. Rank them in terms of color from deepest blue to lightest blue. Record these observations in Data Table 1.
22. Empty each of the test tubes into the sink. Rinse and thoroughly dry each test tube.

Part D. Preparing Dilutions of a Given Molarity

23. Place the five labeled test tubes in the test tube rack. Using a 10-mL graduated cylinder, pour 10 mL of the stock 0.10 M copper(II) sulfate solution into test tube 1. Record the necessary data for test tube 1 in Data Table 2.
24. Rinse the CuSO₄ pipet. Using this pipet, fill the 10-mL graduated cylinder exactly to the 3.8-mL mark with the stock solution. Try not to get any drops of solution on the sides of the cylinder. Make sure that the bottom of the meniscus sits exactly at the 3.8-mL mark. Now using the water pipet, fill the graduated cylinder to the 10-mL mark with distilled or deionized water. Make sure that the bottom of the meniscus sits exactly at the 10-mL mark.
25. Mix the solution in the graduated cylinder according to step 18 by repeatedly filling and emptying the pipet with the solution. Transfer the mixed solution to test tube 2. Rinse the graduated cylinder with water and thoroughly dry it with a paper towel. Rinse the CuSO₄ pipet according to step 16.
26. Record the necessary data for test tube 2 in Data Table 2.
27. Rinse the CuSO₄ pipet. Using this pipet, fill the 10-mL graduated cylinder exactly to the 2.4-mL mark with the stock solution. Try not to get any drops of solution on the sides of the cylinder. Make sure that the bottom of the meniscus sits exactly at the 2.4-mL mark. Now using the water pipet, fill the graduated cylinder to the 10-mL mark with distilled or deionized water. Make sure that the bottom of the meniscus sits exactly at the 10-mL mark.
28. Mix the solution in the graduated cylinder according to step 18 by repeatedly filling and emptying the pipet with the solution. Transfer the mixed solution to test tube 3. Rinse the graduated cylinder with water and thoroughly dry it with a paper towel. Rinse the CuSO₄ pipet according to step 16.
29. Record the necessary data for test tube 3 in Data Table 2.
30. Before proceeding, check your calculations and procedure for preparation of 10 mL of a 0.050 M and a 0.015 M copper(II) sulfate solution by dilution of the 0.10 M stock copper(II) sulfate solution from the Prelab Questions 2 and 3 with your instructor.
31. Using your calculations and written procedure from Prelab Question 2, prepare 10 mL of a 0.050 M copper(II) sulfate solution by diluting the stock solution. Record necessary data for test tube 4 in Data Table 2.
32. Using your calculations and written procedure from Prelab Question 3, prepare 10 mL of a 0.015 M copper(II) sulfate solution by diluting the stock solution. Record necessary data for test tube 5 in Data Table 2.
33. Compare the color of the stock solution and each of the dilutions in test tubes 1–5. Rank them in terms of color from deepest blue to lightest blue. Record these observations in Data Table 2.

Student Worksheet PDF

12032_Student1.pdf