chemistry

Experiment 1Determining the Chemical Formula for Copper Gluconate

Experiment Inventory

Materials 1.4 g Copper Gluconate

10mL 0.5% NaCI solution

2 Aluminum Washers

Aluminum Cup

Matches

Sterno® Cooking Fuel

*Baking Pan

*30 mL Distilled Water

*Toaster or Toaster Oven

*Computer / Internet Access

*Graphing Software

*Camera / Smart Phone

Labware 10 mL Graduated Cylinder

50 mL Beaker

100 mL Beaker

250 mL Glass Beaker

Weigh Boat

Scale

Stir Rod

Bottle Brush

Metal Forceps

Ring and Ring Stand

Ruler

Spatula

*Hot Pad / Towel

*Stopwatch / Timer Note: You must provide the materials listed in *red.

EXPERIMENT 1: DETERMINING THE CHEMICAL FORMULA FOR COPPER GLUCONATE

In this experiment, you will determine the chemical formula of copper gluconate by isolating the copper and calculating the molar ratio of copper and gluconate in the compound.

PROCEDURE

1. Put on your safety glasses and gloves (provided in your safety box).

2. Turn on the scale by pressing the button labeled 0/T. If your scale does not turn on, you may have to remove the battery cover and remove a small strip of plastic from the battery housing. Once the scale is on, press the 0/T button a second time to zero the scale. Make sure that the units are in grams (g). If not, press the M button until the units displayed are in grams.

3. Place the weigh boat on the scale and zero the mass of the weigh boat by pressing the 0/T button. Your scale should now read 0 g.

4. Measure 1.4 g of the copper gluconate onto the weigh boat on the scale. Record this as the copper gluconate mass in

©2018, eScience Labs

Table 2 on the Experiment Data Sheet.

5. Pour the copper gluconate off the weigh boat into the 250 mL glass beaker.

6. Use the 10 mL graduated cylinder to measure and pour 10 mL of 0.5% NaCl into the beaker with the copper gluconate. You may need to gently swirl the solution if all the copper gluconate does not immediately dissolve into the solution.

7. Set up the ring stand in a well-ventilated (but not windy) area with a level, heat resistant surface (Figure 5).

8. Using a ruler, fasten the ring 8 inches up on the ring stand.

9. Place the Sterno® directly beneath the ring of the ring stand. See Figure 5 for an example of the experimental set-up.

10. Remove your safety gloves before performing Step 10. The safety gloves are not fire proof, and wearing them while handling fire is extremely dangerous. Burns with gloves on are worse than without.

11. Thoroughly read all the directions on your Sterno® cooking fuel can. Then, use your spatula to pry open the lid. Put the lid aside, being careful not to touch any contents.

12. Carefully touch a lit match to the Sterno® contents. The contents will flame up immediately. Under bright lights you may not be able to see the flame, but know that it is there. Be sure to blow out the match once the Sterno® is lit.

13. Place the two aluminum washers into the 250 mL beaker containing the copper gluconate and salt solution.

14. Immediately (and carefully) place the 250 mL beaker onto the ring of the ring stand.

15. Start a timer or stopwatch and heat the beaker until the solution becomes clear. Your solution may not turn completely clear, but some color change should be evident. Alternatively, you can also determine when the reaction is complete by looking for the formation of gas bubbles on the surface of the washers. When the formed gas bubbles are gone, the reaction is complete. Do not keep the solution on heat for more than 20 minutes.

16. Use a hot pad or towel to carefully remove the beaker from the heat by grabbing the rim of the beaker (any other part may be too hot) and placing it on a non-flammable surface.

17. Extinguish your Sterno® by placing the cover on top of the can with your forceps. Do not attempt to blow out the flame, as you may create a fire. Once the can is cooled (look at the temperature indicator on the label), snugly fit the cover onto the can and store it in a safe place away from heat or flames.

18. Pour the liquid in the 250 mL beaker into a 50 mL waste beaker.

19. Pour approximately 30 mL distilled water into a 100 mL beaker.

20. Use forceps to carefully pick up a washer and dip it into the 30 mL distilled water.

21. Determine the mass of a aluminum cup. Write it in Table 2.

22. Place the rinsed washer onto the aluminum cup.

23. Hold a washer in place with the stir rod and use the forceps to scrape the copper off the washer into the aluminum cup.

24. Repeat Steps 20-23 for the second washer.

25. Discard the washers.

26. Place the wrapper with copper on a baking pan and put it in the oven at 115 °C (240 °F) to dry the product. Monitor the wrapper and contents, and use a hot pad or towel to carefully remove them from the oven after 15 minutes, or after all of

Figure 5: Ring standset-up.

Note: The copper gluconate may not fully dissolve into solution.

**Carefully observe the set-up. Do not leave the beaker unattended while exposed to the Sterno®. Plastic beakers should never be used with heat. Avoid breathing any fumes.

©2018, eScience Labs

the water has evaporated.

27. After the wrapper has cooled to room temperature, place the wrapper and copper on the scale and determine the mass of the foil and copper. Record this mass in Table 2.

28. Use your camera (or smart phone) to take a picture of the copper on the weigh boat. Be sure to send the picture to your instructor along with your results tables and Post-Lab Questions.

©2018, eScience Labs

Data Sheet Experiment Data Sheet

Table 2. Mass

Compound Mass (g)

Copper Gluconate

Aluminum Cup + Copper

- Aluminum Cup

Copper

Table 3. Givens

Name Given

Copper Gluconate Formula Cu(C6H11Ox)n

Molecular Weight of C 12.01 g/mol

Molecular Weight of H 1.008 g/mol

Molecular Weight of O 16.00 g/mol

Molecular Weight of Cu 63.55 g/mol

Table 4. Unknowns

Unknowns

x=

n=

©2018, eScience Labs

Experiment 1Determining the Chemical Formula for Copper Gluconate

Experiment Inventory

Materials 1.4 g Copper Gluconate

10mL 0.5% NaCI solution

2 Aluminum Washers

Aluminum Cup

Matches

Sterno® Cooking Fuel

*Baking Pan

*30 mL Distilled Water

*Toaster or Toaster Oven

*Computer / Internet Access

*Graphing Software

*Camera / Smart Phone

Labware 10 mL Graduated Cylinder

50 mL Beaker

100 mL Beaker

250 mL Glass Beaker

Weigh Boat

Scale

Stir Rod

Bottle Brush

Metal Forceps

Ring and Ring Stand

Ruler

Spatula

*Hot Pad / Towel

*Stopwatch / Timer Note: You must provide the materials listed in *red.

EXPERIMENT 1: DETERMINING THE CHEMICAL FORMULA FOR COPPER GLUCONATE

In this experiment, you will determine the chemical formula of copper gluconate by isolating the copper and calculating the molar ratio of copper and gluconate in the compound.

PROCEDURE

1. Put on your safety glasses and gloves (provided in your safety box).

2. Turn on the scale by pressing the button labeled 0/T. If your scale does not turn on, you may have to remove the battery cover and remove a small strip of plastic from the battery housing. Once the scale is on, press the 0/T button a second time to zero the scale. Make sure that the units are in grams (g). If not, press the M button until the units displayed are in grams.

3. Place the weigh boat on the scale and zero the mass of the weigh boat by pressing the 0/T button. Your scale should now read 0 g.

4. Measure 1.4 g of the copper gluconate onto the weigh boat on the scale. Record this as the copper gluconate mass in

©2018, eScience Labs

Table 2 on the Experiment Data Sheet.

5. Pour the copper gluconate off the weigh boat into the 250 mL glass beaker.

6. Use the 10 mL graduated cylinder to measure and pour 10 mL of 0.5% NaCl into the beaker with the copper gluconate. You may need to gently swirl the solution if all the copper gluconate does not immediately dissolve into the solution.

7. Set up the ring stand in a well-ventilated (but not windy) area with a level, heat resistant surface (Figure 5).

8. Using a ruler, fasten the ring 8 inches up on the ring stand.

9. Place the Sterno® directly beneath the ring of the ring stand. See Figure 5 for an example of the experimental set-up.

10. Remove your safety gloves before performing Step 10. The safety gloves are not fire proof, and wearing them while handling fire is extremely dangerous. Burns with gloves on are worse than without.

11. Thoroughly read all the directions on your Sterno® cooking fuel can. Then, use your spatula to pry open the lid. Put the lid aside, being careful not to touch any contents.

12. Carefully touch a lit match to the Sterno® contents. The contents will flame up immediately. Under bright lights you may not be able to see the flame, but know that it is there. Be sure to blow out the match once the Sterno® is lit.

13. Place the two aluminum washers into the 250 mL beaker containing the copper gluconate and salt solution.

14. Immediately (and carefully) place the 250 mL beaker onto the ring of the ring stand.

15. Start a timer or stopwatch and heat the beaker until the solution becomes clear. Your solution may not turn completely clear, but some color change should be evident. Alternatively, you can also determine when the reaction is complete by looking for the formation of gas bubbles on the surface of the washers. When the formed gas bubbles are gone, the reaction is complete. Do not keep the solution on heat for more than 20 minutes.

16. Use a hot pad or towel to carefully remove the beaker from the heat by grabbing the rim of the beaker (any other part may be too hot) and placing it on a non-flammable surface.

17. Extinguish your Sterno® by placing the cover on top of the can with your forceps. Do not attempt to blow out the flame, as you may create a fire. Once the can is cooled (look at the temperature indicator on the label), snugly fit the cover onto the can and store it in a safe place away from heat or flames.

18. Pour the liquid in the 250 mL beaker into a 50 mL waste beaker.

19. Pour approximately 30 mL distilled water into a 100 mL beaker.

20. Use forceps to carefully pick up a washer and dip it into the 30 mL distilled water.

21. Determine the mass of a aluminum cup. Write it in Table 2.

22. Place the rinsed washer onto the aluminum cup.

23. Hold a washer in place with the stir rod and use the forceps to scrape the copper off the washer into the aluminum cup.

24. Repeat Steps 20-23 for the second washer.

25. Discard the washers.

26. Place the wrapper with copper on a baking pan and put it in the oven at 115 °C (240 °F) to dry the product. Monitor the wrapper and contents, and use a hot pad or towel to carefully remove them from the oven after 15 minutes, or after all of

Figure 5: Ring standset-up.

Note: The copper gluconate may not fully dissolve into solution.

**Carefully observe the set-up. Do not leave the beaker unattended while exposed to the Sterno®. Plastic beakers should never be used with heat. Avoid breathing any fumes.

©2018, eScience Labs

the water has evaporated.

27. After the wrapper has cooled to room temperature, place the wrapper and copper on the scale and determine the mass of the foil and copper. Record this mass in Table 2.

28. Use your camera (or smart phone) to take a picture of the copper on the weigh boat. Be sure to send the picture to your instructor along with your results tables and Post-Lab Questions.

©2018, eScience Labs

Data Sheet Experiment Data Sheet

Table 2. Mass

Compound Mass (g)

Copper Gluconate

Aluminum Cup + Copper

- Aluminum Cup

Copper

Table 3. Givens

Name Given

Copper Gluconate Formula Cu(C6H11Ox)n

Molecular Weight of C 12.01 g/mol

Molecular Weight of H 1.008 g/mol

Molecular Weight of O 16.00 g/mol

Molecular Weight of Cu 63.55 g/mol

Table 4. Unknowns

Unknowns

x=

n=

©2018, eScience Labs