Experiment 1: Determining the Chemical Formula for CopperGluconate The experiments in this lab use a compound named coppergluconate. This compound can be formed when gluconic acid (C6H12O7)and copper solutions react with copper (II) carbonates or copperhydroxide. Copper gluconate has a variety of uses and applications.For example, copper gluconate is used as a primary ingredient inthe breath mint Certs®. It is also used as a source of copper innutritional supplements. Your task will be to determine thechemical formula of the compound by isolating the copper anddetermining the molar ratio of copper and gluconate in thecompound. Figure 3: Certs® Figure 3: Certs® Materials: 1 g Coppergluconate 10 mL 0.5% Salt, NaCl 10 mL Graduated cylinder Scale (1)50 mL Beaker 250 mL Glass beaker 2 Aluminum washers Sterno® Ringstand Ring for ring stand Stir rod Matches Cupcake wrapper *Oven*Hot pad or towel *Baking pan *20 mL Distilled Water *Kitchen tongs*You must provide Procedure Put the 250 mL beaker on the scale andtare the scale. Measure 1.0 g of the copper gluconate in the beakeron the scale. Record the exact mass in the Data section below. Usethe graduated cylinder to measure and pour 10 mL 0.5% NaCl into thebeaker with the copper gluconate. You may need to gently swirl thesolution if all the copper gluconate does not immediately suspendinto the solution. Add two aluminum washers to the solution. Fastenthe small ring approximately 6 - 10 inches up on the ring stand andplace the beaker on the ring Place the Sterno® directly beneath thebeaker. Remove the inner cap on the Sterno® and ignite the innercontents with the matches. Heat the beaker until solution clears.Your solution may not turn completely clear, but some color changeshould be evident. Alternatively you can also determine when thereaction is complete by looking for the formation of gas bubbles onthe surface of the washers. When the formed gas bubbles are gone,then the reaction is complete. Note: Carefully monitor the set-upwhile the Sterno® is in use. You may need to adjust the height ofthe ring/beaker to ensure that the beaker is heated enough; and, toavoid exposing the beaker from high temperatures. **Carefullyobserve the set-up you choose!! Do not leave the beaker unattendedwhile exposed to the Sterno®. Plastic beakers should never be usedwith heat.** Carefully remove the beaker from heat, and use forcepsto replace the lid on the Sterno®. Decant (pour) the clear liquidinto a 50 mL beaker. When all that remains in the original beakerare the copper plated washers, rinse the washers with distilledwater and decant the remaining liquid, being careful not to loseany copper, into a container. This water can be disposed of down asink drain. Repeat this process three times. Remove the firstwasher and use the stir stick to scrape the copper into the metalcupcake wrapper. Rinse the washer with distilled water to be sureall copper is recovered into the wrapper. Repeat the process forthe second washer, scraping the copper into the same wrapper. Placethe wrapper on a baking pan and put it in the oven at 115 °C (239°C) to dry the product. Monitor the wrapper and contents and use ahot pad or towel to carefully remove them from the oven after 45minutes, or after all of the water has evaporated. After thewrapper has cooled to room temperature, empty the dried copper fromthe wrapper onto the scale and weigh the final mass.

Why is it important in this experiment to be accurate in allyour measurements?

List the measurements you will take in this experiment.

What chemical wastes are produced in this reaction?

Record the mass in the Data section below.

Data: Mass of copper gluconate (initial, see Step 2):_____________________

Mass of copper (final; see Step 13): _____________________

Calculations Mass of copper recovered:

Moles of copper :

Mass of gluconate:

Moles of gluconate:

Chemical formula:

1. What is the chemical formula of copper gluconate?

2. List two sources of error in the experiment and explain theimpact they had on the results.

3. Create a pie chart showing the percent composition for eachelement in the compound copper gluconate, clearly label eachelement and the percentage.

4. Copper chloride can be used as a source of copper for thisexperiment, but copper gluconate is preferred due the fact that itis a “green” compound. Discuss the environmental