Using your own lab results, show your calculations for your moles of copper produced, homework help

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timer Asked: May 21st, 2017
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Question Description

A. Place a plastic weighboat on the scale and tare (re-zero) the scale.

B. Measure 1.0 g of the copper gluconate in the weighboat on the scale. If you don’t land exactly on 1.0,

that’s OK. Just get as close as you can, and record the exact mass in Table 1 below.
C. Transfer all of the copper gluconate into a glass 250 mL beaker. Try not to leave any behind in the

weighboat, as this will affect your calculation later.
D. Using a clean, dry 10 mL graduated cylinder (you may want to first rinse with distilled water prior

to using, then dry), measure 10.0 mL of 0.5% NaCl solution, and pour it into the beaker with the copper gluconate. If you need to use a pipette to help transfer the NaCl into the graduated cylinder, that’s fine. You may need to gently swirl or stir (with your glass stirring rod) the solution if all the copper gluconate does not immediately suspend into the solution.

E. Place 2 aluminum (Al) washers into the beaker with the solution.
F. Fasten your iron ring to your ring stand, about 6-10 inches high. Place your beaker on the iron ring. It

should fit just enough inside the ring where it won’t fall, but if yours does not fit as nicely as you’d like, you can place your watchglass over the ring to create a more stable platform on which to sit your beaker. Be very careful that your beaker does not fall, or you will lose your data for this experiment, not to mention have a mess to clean up.

G. Place your Sterno® fuel underneath your beaker. This will be your heat source and take the place of a traditional Bunsen burner. Your final setup should look similar to this:

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Lab 3 Assignment 5/21/17, 9:23 AM Lab 3 Assignment Part 1 of 1 - 4.0 Points Question 1 of 7 Using your own lab results, show your calculations for your moles of copper produced. You must show all work to receive credit. Maximum number of characters (including HTML tags added by text editor): 60,000 Count Characters Show/Hide Rich-Text Editor 4.0 Points Question 2 of 7 Using your own lab results, show your calculations for your moles of gluconate. You must show all work to receive credit. Maximum number of characters (including HTML tags added by text editor): 60,000 Count Characters Show/Hide Rich-Text Editor 3.0 Points https://edge.apus.edu/portal/tool/5c6aaba6-5e19-4f58-a7a8-474b22f73d06/jsf/delivery/beginTakingAssessment Page 1 of 3 Lab 3 Assignment 5/21/17, 9:23 AM Question 3 of 7 Using your own lab results, determine the chemical formula of copper gluconate. You must show all work (not just the formula) to receive credit. Maximum number of characters (including HTML tags added by text editor): 60,000 Count Characters Show/Hide Rich-Text Editor 2.0 Points Question 4 of 7 List two sources of error in the experiment and explain the impact they had on the results. Maximum number of characters (including HTML tags added by text editor): 60,000 Count Characters Show/Hide Rich-Text Editor 3.0 Points Question 5 of 7 Using your own lab results, calculate the percent composition of copper and the percent composition of gluconate in the compound copper gluconate. Clearly label each ion (copper and gluconate) and the percentage. You must show all work (not just the formula) to receive credit. Maximum number of characters (including HTML tags added by text editor): 60,000 Count Characters Show/Hide Rich-Text Editor https://edge.apus.edu/portal/tool/5c6aaba6-5e19-4f58-a7a8-474b22f73d06/jsf/delivery/beginTakingAssessment Page 2 of 3 Lab 3 Assignment 5/21/17, 9:23 AM 4.0 Points Question 6 of 7 Please upload (in PDF format) your experimental setup picture as explained in Step 7 of the Lab 03 Document. This must be a single picture PDF file. NOTE: If your picture is not clear or any part of it cannot be read by your instructor, you will not receive credit. Click "Browse" to locate your file and then click "Upload" to upload your file. (Maximum file size: 20MB) File: Choose File no file selected Upload 5.0 Points Question 7 of 7 Please upload (in PDF format) your dried copper picture as explained in Step 8 of the Lab 03 Document. This must be a single picture PDF file. NOTE: If your picture is not clear or any part of it cannot be read by your instructor, you will not receive credit. Click "Browse" to locate your file and then click "Upload" to upload your file. (Maximum file size: 20MB) File: Save Choose File no file selected Upload Exit https://edge.apus.edu/portal/tool/5c6aaba6-5e19-4f58-a7a8-474b22f73d06/jsf/delivery/beginTakingAssessment Page 3 of 3 Lab 3: Compound Formulas Introduction 1. Open up your student lab manual (PDF) that came with your kit. You can either access it from the DVD that came inside your kit, or else download it from www.esciencelabs.com (you will first have to register your kit, which you should have already done by following the directions in Lesson 1). 2. Access “Lab 4: Compound Formulas” in your student lab manual (pp. 63 – 68), and read the sections titled Introduction, Chemical Compounds, Percent Compositions, Molar Concentration, Molar Ratios, and answer the pre-lab questions (p. 63 – 65). 3. Visit www.esciencelabs.com, log in, and click on the Student tab. 4. Under the heading “Kit Resources” on the eScience website, click on General Chemistry Version 1 (or Version 3), and again on General Chemistry Version 1 (or Version 3) on the next screen. 5. Click on the link “Matter and Structure,” then find and watch the following slideshow animations and lab drills (NOTE: For the slideshow, you will have to click on the “Audio” button to hear the narration): Concept Animation: Compound Formulas Chemical Formulas Lab Drill: Compound Formulas Objective To experimentally (i.e. not just look it up or use the naming rules!) determine the chemical formula of copper gluconate by chemically isolating the copper to determine the mole ratio of copper to gluconate in the compound. Materials Procedure NOTE: Gluconate is a polyatomic ion, (C12H22O14-), so think of this entire group of atoms as a single ion unit (in other words, just like Cl in the example shown on p. 65 in the eScience Lab Manual). Your task in this lab is to determine how many moles of both copper ions and gluconate ions are present in your sample, then set those molar values as a ratio to one another to determine the formula. For example, if at the end of your experiment you calculate that you have x moles of copper, and y moles of gluconate, then you write the formula as Cux (C12H22O14)y, then follow the procedure as shown on p. 65 of the lab manual. 6. Complete Experiment 1: Determining the Chemical Formula for Copper Gluconate. A. Place a plastic weighboat on the scale and tare (re-zero) the scale. B. Measure 1.0 g of the copper gluconate in the weighboat on the scale. If you don’t land exactly on 1.0, that’s OK. Just get as close as you can, and record the exact mass in Table 1 below. C. Transfer all of the copper gluconate into a glass 250 mL beaker. Try not to leave any behind in the weighboat, as this will affect your calculation later. D. Using a clean, dry 10 mL graduated cylinder (you may want to first rinse with distilled water prior to using, then dry), measure 10.0 mL of 0.5% NaCl solution, and pour it into the beaker with the copper gluconate. If you need to use a pipette to help transfer the NaCl into the graduated cylinder, that’s fine. You may need to gently swirl or stir (with your glass stirring rod) the solution if all the copper gluconate does not immediately suspend into the solution. E. Place 2 aluminum (Al) washers into the beaker with the solution. F. Fasten your iron ring to your ring stand, about 6-10 inches high. Place your beaker on the iron ring. It should fit just enough inside the ring where it won’t fall, but if yours does not fit as nicely as you’d like, you can place your watchglass over the ring to create a more stable platform on which to sit your beaker. Be very careful that your beaker does not fall, or you will lose your data for this experiment, not to mention have a mess to clean up. G. Place your Sterno® fuel underneath your beaker. This will be your heat source and take the place of a traditional Bunsen burner. Your final setup should look similar to this: H. (You will be taking a picture as part of this step—see Step 7 below). Remove the inner cap on the Sterno® and ignite the inner contents with the matches. Heat the beaker until the solution clears. 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, then the reaction is complete. Make sure your washers are completely submerged in solution. You may have to rock or swirl or tilt the beaker during the reaction to ensure this. But careful…the beaker will be HOT! Note: Carefully monitor the set-up while the Sterno® is in use. You may need to adjust the height of he ring/beaker to ensure that the beaker is heated enough; and, to avoid exposing the beaker from high heat. **Carefully observe the set-up you choose!! Do not leave the beaker unattended while exposed to the Sterno®. Plastic beakers should never be used with heat.** I. When the reaction is complete, carefully remove the beaker from heat, and use forceps to replace the lid on the Sterno®. Carefully decant (pour off) the clear(ish) liquid into a 50 mL beaker. J. When all that remains in the original beaker are the copper plated washers, rinse the washers with distilled water (dH2O) and again decant the remaining liquid, being careful not to lose any copper, into a container. This water can be disposed of down a sink drain. Repeat this rinsing process three times. K. Place a metal cupcake wrapper on the scale and record its mass in Table 1 below. Remove the wrapper from the scale, and carefully remove the first washer and use the stir stick to scrape the copper into the metal cupcake wrapper. L. Rinse the washer with just a little dH2O over the wrapper just to be sure all copper is recovered into the wrapper. Don’t worry, this water will evaporate away when you dry the product (dessicate it) in the oven. However, use as little dH2O as possible, since the more you use, the longer it will take to dry. M. Repeat the process for the second washer, scraping/washing the copper into the same wrapper. N. Place the wrapper on a baking pan and put it in the oven at 115 °C (239 °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 45 minutes, or after all of the water has evaporated. O. (You will be taking a picture as part of this step—see Step 8 below). After the wrapper has cooled to room temperature, weigh the final mass of the wrapper with the copper inside it. Record the mass in Table 1 below. Subtract this mass from the starting mass of copper gluconate to determine how much gluconate was in the original sample. Record this value in Table 1. 7. After completing the experimental setup and beginning the experiment (Step 6-H above), make a label with your name, the lab title, and the date, and place it next to your experimental setup. Unless all three—your name, the lab title, and the date are on the label and legible, you will not receive credit. Take a picture of each of your setup, and make sure your label can be read clearly in your picture. Save this picture in a PDF document in order to submit it in the Lab 3 Assignment. 8. Once your experiment is complete, take a picture of your dried copper being weighed on the scale. The copper and the mass value must both be visible in the picture, as well as a label with your name, the lab title, and the date. Unless all three—your name, the lab title, and the date are on the label and legible, you will not receive credit. Save this picture in a PDF document in order to submit it in the Lab 3 Assignment. 9. Clean up your lab and put away your materials. Wash your glassware (and plasticware) with warm water and soap. To minimize spotting and mineral contamination, it is best to do a final rinse with dH2O. Dry your glassware (or leave set to dry) and put it away. All chemicals used in this lab can be safely washed down the sink. Results 10. Make a data table in either Word or Excel that shows the data necessary to determine the formula of your compound. All work must be shown neatly and clearly as part of your table. Your table should look something like this: Table 1: Copper Gluconate Formula Data Mass (g) of copper Mass (g) of wrapper gluconate (Show all work to receive credit) Moles of Cu recovered: Moles of Gluconate: Mass (g) of wrapper + Cu Mass (g) of Cu Mass (g) of gluconate Experimental Chemical Formula: 11. You should have 2 PDF documents when finished with this lab—1 for your experimental setup, and 1 containing your dried copper being weighed. All pictures and labels must be clear or they will not receive credit. 12. Answer the post-lab questions below. 13. Go back into the course classroom, click on Tests & Quizzes located on the left side menu, and complete the Lab 3 Assignment posted there. Remember, it is in a quiz format, but it is not a quiz. You can access it as many times as you wish while entering your answers, and it is not timed. Just be sure that you do not actually click “Submit” until you are ready to be graded. NOTE: There is space provided in the student manual at the end of each lab for you to write a lab report. You will NOT be writing lab reports in this class. You are only being graded according to the last step listed above. Post-lab Questions 1. List two sources of error in the experiment and explain the impact they had on the results. 2. Using your own lab results, calculate the percent composition for each element in the compound copper gluconate. Clearly label each element and the percentage. You must show all work (not just the formula) to receive credit. ...
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